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INTEGRATED PATHOLOGY SERVICE

GENERAL PATHOLOGY DOCUMENT

Chemistry Test User Guide

A-E

[PD-CHM-TestGuide1]

AUTHOR:

Samantha Nelson

APPROVED BY:

Steve Short

DATE OF ISSUE:

20/09/2019

DATE EFFECTIVE FROM:

20/09/2019

VERSION NO:

1

REVIEW INTERVAL:

Biennial

COPY:

1

LOCATION OF COPIES:

1 Electronic – Q-Pulse

2 Electronic - StaffNet

Assay

Acetylcholine receptor antibody

Synonyms

ACRA, ACHR

Sample type

Gold top

Test instructions

Referral laboratory

Immunology department

Churchill hospital

Headington

Oxford

OX3 7LJ

Turnaround time

2 Weeks

Test indications

Acetylcholine receptor antibodies are a highly sensitive and specific marker for generalised myasthenia gravis. Present in 90% of patients with myasthenia gravis

Reference intervals

Negative is <5 X10-10 mole per litre

Interferences

Assay

Acylcarnitines

Synonyms

Total carnitines, metabolic

Sample type

Blood spot (Guthrie card)

Test instructions

Bloodspot card. Two > 7mm diameter bloodspots. Blood must be soaked through and not multi-spotted

Referral laboratory

Inherited Metabolic Diseases Unit at St Thomas' Hospital

0207 188 9652

St Thomas' Hospital North Wing

4th Floor London

SE1 7EH

Turnaround time

10 days

Test indications

Used in the investigation of fatty chain oxidation

Reference intervals

Contact referral laboratory to discuss

Interferences

Assay

Adrenocorticotrophic hormone (ACTH)

Synonyms

ACTH

Sample type

EDTA Plasma (350 uL)

Test instructions

Must be sent to laboratory ASAP to be spun and frozen.

Referral laboratory

Reference Biochemistry Department at King's College Hospital

020 3299 4107

King's College Hospital

Denmark Hill

London

SE5 9RS

Turnaround times

7-10 days

Test indications

Used in the investigation of pituitary-adrenal disorders relating to glucocorticoids

Reference intervals

<46 ng/L

Interferences

Assay

Alanine Aminotransferase

Synonyms

ALT

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Elevated serum ALT is found in hepatitis, cirrhosis, obstructive jaundice, carcinoma of the liver, and chronic alcohol abuse. ALT is only slightly elevated in patients who have an uncomplicated myocardial infarction.

Reference intervals

5-40 u/L

Interferences

Assay

Albumin

Synonyms

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Albumin is a key plasma protein. Low levels are seen in liver disease, burns, malabsorption, and is losses through the kidneys (proteinuria) and stool. Raised levels usually indicate dehydration. During illness albumin tends to move towards the extravascular compartment; the resulting lowered concentration of albumin is the most common change in plasma proteins in pathological stress.

-Concentrations less than 30 g/L usually signify serious organic disease

-The lowest values (10-20 g/L) occur in nephrotic syndrome and protein losing enteropathy

-Concentrations below 20 g/L are generally accompanied by oedema.

Reference intervals

< 11 months: 30-45 g/L, 11 months- 15 years: 30-50 g/L, > 15: 35-50 g/L

Interferences

Assay

Alkaline phosphate

Synonyms

ALP, ALKP

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

A rise in the alkaline phosphatase occurs with all forms of cholestasis, particularly with obstructive jaundice. It is also elevated in diseases of the skeletal system, such as Pagets disease, hyperparathyroidism, rickets and osteomalaecia, as well as with fractures and malignant tumours. A considerable rise in the alkaline phosphatase activity is sometimes seen in children and juveniles. It is caused by increased osteoblast activity following accelerated bone growth.

Reference intervals

< 4 weeks: 70-380 u/L, 4 weeks- 15 years: 60-425 u/L, > 15 years: 30-130 u/L

Interferences

Assay

Alkaline phosphate isoenzyme

Synonyms

Sample type

SST (Gold top)

Test instructions

Referral laboratory

Immunochemistry Laboratory at King's College Hospital

020 3299 4130

King's College HospitalDenmark HillLondon SE5 9RS

Turnaround time

1-2 weeks

Test indications

Used to distinguish between bone and liver origin of elevated alkaline phosphatase. However gamma glutamyl transferase (GGT) which is performed daily in the laboratory can usually give the same information more quickly since gamma GT is not present in the bone.

Reference intervals

Contact referral laboratory

Interferences

Assay

Alpha-1-antitrypsin

Synonyms

A1AT, AAT

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

A1AT levels are primarily used when assessing a diagnosis of acute hereditary A1AT deficiency as a cause of neonatal hepatitis accompanied by progressive liver cirrhosis in early childhood, orwhen severe pulmonary emphysema occurs in adults due to the prevalence of leukocyte elastase, which can lead to unrestrained proteolytic degradation of the pulmonary parenchymal cells.

Samples with low AAT levels are referred for A1AT phenotyping to exclude hereditary A1AT deficiencies

Reference intervals

< 52 weeks: 0.9-1.8 g/L, 52 weeks- 15 years: 1.1-2.1 g/L, > 15 years: 2.2-2.6 g/L.

Interferences

Assay

Alpha-fetoprotein

Synonyms

AFP

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

AFP is an albumin like glycoprotein. AFP is used as a tumour marker for germ cell/testicular tumours and hepatocellular carcinomas.

Also raised in other cancers (colorectal, gastric, lung, pulmonary) and some benign conditions (liver regeneration). It is found in high concentrations in foetal serum and in very low concentrations in normal adult serum (<10 iu/mL) but may range from normal to very high levels (>100,000 iu/mL) in the sera of patients with hepatocellular or yolk-sac derived (endodermal sinus) cancers. Elevations up to 500 iu/mL frequently occur in association with a variety of non-malignant liver diseases, but levels above this are suugestive of an AFP producing tumour. However, a significant number of tumours have a normal AFP at diagnosis. In benign disease AFP elevation is either constant or transient. In pregnancy maternal serum levels may be used to assess the risk of neural tube defects and Down syndrome (when combined with other markers)

Reference intervals

<9 iu/mL

Interferences

Assay

Aluminium

Synonyms

Sample type

Trace elements tube (royal blue top)

Test instructions

Volume required: 500µl

Referral laboratory

Trace Elements Laboratory at King's College Hospital

020 3299 3008

King's College Hospital Bessemer Wing –

Top Floor

Denmark Hill

London

SE5 9RS

Turnaround time

1- 2 weeks

Test indications

Used in the investigation of aluminium toxicity

Reference intervals

Normal serum aluminium concentration is < 0.4 µmol/L in subjects with no history of chronic renal failure (CRF). It is however, common for concentrations to be above >0.4µmol/L in renal patients

Interferences

Assay

Amino Acid (Plasma)

Synonyms

Metabolic screen

Sample type

Lithium heparin plasma

Test instructions

Minimum sample volume 500 uL plasma. Lipaemic samples are unsuitable.

Referral laboratory


0207 188 9652

St Thomas' HospitalNorth Wing - 4th FloorLondonSE1 7EH

Turnaround time

1-2 weeks

Test indications

Used in the investigation of amino acid disorders, including urea cycle defects and some organic acid disorders.

Reference intervals


Interferences

Assay

Amino acids (Urine)

Synonyms

Sample type

Random urine, universal white top

Test instructions

Minimum sample volume 2 mL urine. Acidified samples are unsuitable.

Referral laboratory


0207 188 9652

St Thomas' HospitalNorth Wing - 4th FloorLondonSE1 7EH

Turnaround time

2 weeks

Test indications

Urine amino acids is no longer used as a metabolic screen (please use plasma amino acids). It is available for the investigation of renal transport disorders (e.g. cystinuria), the assessment of renal tubular dysfunction (e.g. Fanconi syndrome, mitochondrial disease) and for some other specific disorders (e.g. hypophosphatasia).

Reference intervals

Qualitative report

Interferences

Assay

Amiodarone

Synonyms

Sample type

SST (Gold top)

Test instructions

Referral laboratory

Toxicology Laboratory The Academic Centre Llandough Hospital Penarth CF64 2XX

Tel: 029 2071 6894

Turnaround time

6 weeks

Test indications

Used in the therapeutic drug monitoring of amiodarone

Reference intervals


Interferences

Assay

Ammonia

Synonyms

NH3

Sample type

Lithium heparin (Green top)

Test instructions

Must be brought to the laboratory ASAP on ice.

Referral laboratory

N/A

Turnaround time

Test indications

Used in the diagnosis and monitoring of urea cycle disorders and Reyes syndrome

Reference intervals

<4 weeks: <100 umol/L, >4 weeks: <50 umol/L

Interferences

Assay

Amylase (Serum)

Synonyms

Amy

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Because of the scarcity of specific clinical symptoms of pancreatic diseases, amylase determinations are of considerable importance in pancreatic diagnostics. They are mainly used in the diagnosis and monitoring of acute pancreatitis. Very high levels support the diagnosis of pancreatitis. However other conditions which present with abdominal pain may have very elevated levels: Afferent loop obstruction, absorption through the peritoneum as in biliary peritonitis, damage to the pancreas or its blood supply. Hyperamylasaemia does not, however, only occur with acute pancreatitis or in the inflammatory phase of chronic pancreatitis, but also in renal failure (reduced glomerular filtration), tumours of the lungs or ovaries, pulmonary inflammation, diseases of the salivary gland, diabetic ketoacidosis, cerebral trauma, surgical interventions or in the case of macroamylasaemia

Reference intervals

<14 days: 3-10 iu/L, 14 days to 14 weeks: 2 -22 iu/L, 14 weeks to 1 year: 3-50 iu/L, 1 year- 19 years: 25-101 iu/L, >19 years: 25-101 iu/L

Interferences

Assay

Amylase (Urine)

Synonyms

Sample type

Random urine sample in universal container

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Used in the investigation of raised serum amylase activity, to exclude macroamylasaemia

Reference intervals

u/L

Interferences

Assay

Androstenedione

Synonyms

Sample type

SST (Gold top)

Test instructions

Referral laboratory

Clinical Biochemistry - Blood Sciences at King's College Hospital

020 3299 4126

King's College HospitalBessemer WingDenmark HillLondon SE5 9RS

Turnaround time

14 working days

Test indications

Used in the investigation of endocrinology disorders

Reference intervals

Adult Females: 1.4 – 14.3 nmol/L

Adult Males: 1.4 – 9.1 nmol/L

Interferences

Assay

Angiotensin converting enzyme

Synonyms

ACE

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Useful for monitoring the activity of sarcoidosis but not sensitive enough to be used in diagnosis.

Reference intervals

20-70 u/L

Interferences

Assay

Arsenic

Synonyms

Sample type

EDTA (Purple top) or 24 hour urine in acid washed bottle

Test instructions

4 mL EDTA whole blood or 20 mL urine

Referral laboratory


020 3299 3008

King's College HospitalBessemer Wing - Top FloorDenmark HillLondon

SE5 9RS

Turnaround time

7-10 working days

Test indications

Used in the investigation of arsenic poisoning

Reference intervals

Blood < 0.13 µmol/L

Urine < 0.13 µmol/24 h (Inorganic arsenic)

Interferences

Assay

Aspartate transaminase

Synonyms

AST

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

The enzyme aspartate aminotransferase (AST) is widely distributed in tissues, principally: hepatic, cardiac, muscle, and kidney. Elevated serum levels are found in diseases involving these tissues

Reference intervals

5-40 u/L

Interferences

Assay

Adalimumab

Synonyms

Sample type

SST (Gold top)

Test instructions

Referral laboratory

Reference Chemistry Laboratory at St Thomas'

0207 188 1264

4th floor, North WingSt Thomas' HospitalWestminster Bridge RoadLondon SE1 7EH

Turnaround time

2 Weeks

Test indications

The measurement of Adalimumab is a useful tool in managing patients who fail to respond (primary failure) or who go on to lose response (secondary failure) to treatment. Monitoring drug levels allows for a personalised approach to drug optimisation by appropriate dose escalation/de-escalation or drug switching/withdrawal.

Measured alone or as part of a profile including anti-Adalimumab antibodies.

Reference intervals

Lower limit of the therapeutic range is yet to be established, however levels of greater than 5 µg/mL appear to be adequate. This information will be updated as we refine the therapeutic range. Test interpretation requires full clinical information: drug dosage/frequency, previous exposure to other biologics, time of sampling, duration of therapy and clinical assessment.

Interferences

Assay

Bicarbonate

Synonyms

CO2

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Used in the diagnosis and treatment of many disorders that are associated with acid-base imbalance in metabolic and respiratory systems.

Reference intervals

< 15 years: 19-28 mmol/L , > 15 years: 22-29

Interferences

Assay

Bile acids

Synonyms

BA

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Serum total bile acids is used as an indicator of intra-hepatic cholestasis in pregnancy. When the bile flow is stopped or slowed down, this causes a build up of bile acids in the liver which can spill into the bloodstream, and leads to significantly increased serum BA levels.

Reference intervals

<10 umol/L

Interferences

Assay

Bilirubin (Total)

Synonyms

TBIL, LFT

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Total bilirubin forms part of routine liver screen. Unconjugated bilirubin can increase in circulation when a disease or a conditions produces bilirubin faster than the liver can metabolise it. Bile duct obstruction or damage to hepatocellular structure causes increases of both conjugated and unconjugated bilirubin in circulation.

Reference intervals

<1 year: 1-12 umol/L,

1-9 years: 1-7 umol/L,

9-12 years: 1-9 umol/L


15-19 years: 2-14 ummol/L

>19 years: 2-21 umol/L

Interferences

Comment

In the absence of abnormal LFTS a conjugated/ total bilirubin ratio <0.3 most likely represents Gilbert's syndrome.

Assay

Biotinidase

Synonyms

Sample type

Lithium heparin (Green top)

Test instructions

Referral laboratory

Cardiff

Turnaround time

Test indications

Used in the investigation of biotinidase deficiency, which may cause seizures

Reference intervals


Interferences

Assay

Brain natriuretic peptide

Synonyms

BNP

Sample type

EDTA (Pink top)

Test instructions

Must be analysed within 4 hours

Referral laboratory

N/A

Turnaround time

Test indications

Reference intervals

<100 ng/L

Interferences

Assay

C1 Esterase inhibitor

Synonyms

C1E

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

Sheffield immunology & Protein reference unit

Department of Immunology

PO Box 894

Sheffield

S5 7YT

Turnaround time

2 Weeks

Test indications

Used for the diagnosis of angioneurotic oedema.

Reference intervals

C1 esterase inhibitor: 0.15-0.35 g/L

C1 esterase Inhibitor activity: 70-150 %

Interferences

Assay

CA 19-9

Synonyms

CA199

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Cancer antigen 19-9 (CA19-9) is neither a tumour-specific nor organ-specified antigen. Its main diagnostic relevance is in the diagnosis, monitoring and detection of recurrence of patients with pancreatic, hepato-biliary and gastric cancer.

Reference intervals

<37 U/mL

Interferences

Comment

Tumour markers are not diagnostic. They are of use primarily for monitoring treatment or detection of relapse. Normal values do not exclude malignancy.

Assay

CA 125

Synonyms

CA125

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

This is a tumour marker for ovarian carcinoma. Moderate elevations may be seen in non-malignant conditions, e.g. pregnancy, menstruation, endometriosis , ascites, cirrhosis, renal failure, acute pancreatitis, peritonitis and in other inflammatory pelvic diseases. High concentrations are more likely to be associated with malignancy. 98% of post-menopausal and 49% of pre-menopausal women with a concentration >70 U/mL have malignant disease. CA125 > 35 U/mL are seen in 50% of patients with Stage 1 ovarian carcinoma and over 90% in Stage 2,3 or 4 disease. Increased CA125 also occurs in patients with non-ovarian malignancy; other gynaecological cancer, 50% of all intra-abdominal cancers and in advanced lung and breast cancer.

Reference intervals

<35 U/mL

Interferences

Comment


Assay

C-Reactive protein

Synonyms

CRP

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

A sensitive acute phase protein. In inflammatory bowel disease CRP correlates with relapse, remission and response to therapy. In rheumatology CRP levels correlate with disease activity in rheumatoid arthritis, polyarteritis nodosa, giant cell arteritis and polymyalgia rheumatic. In infectious disease CRP is elevated in bacterial, fungal and parasitic disease. Viral infection may also elevate CRP but not to the same degree as with bacteria.

Reference intervals

<5 mg/L

Interferences

Assay

Caeruloplasmin

Synonyms

CAER, CRPM

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Decreased concentrations of caeruloplasmin occur due to both primary (genetic) and secondary deficiencies. Primary deficiency due to a deletion of the caeruloplasmin gene has been reported. Secondary deficiencies where there is insufficient incorporation of copper into the caeruloplasmin molecule are significantly more common. These include the recessive autosomal hepatolenticular degeneration associated with Wilsons disease. As caeruloplasmin is a sensitive reactant to the acute phase, increases occur during acute and chronic inflammatory processes (peaking 4-20 days post acute insult).

Reference intervals

< 2 months: 0.07-0.24 g/L

2-6 months: 0.14-0.33 g/L

6 month – 1 year: 0.14-0.39 g/L

1-8 years: 0.22-0.43 g/L

8-14 years: 0.21-0.40 g/L

14-19 years (Male): 0.17-0.35 g/L

14-19 years (Female): 0.21-0.43 g/L

>19: 0.20-0.60 g/L

Interferences

Assay

Calcitonin

Synonyms

Sample type

SST (Gold top)

Test instructions

Must be sent to the laboratory ASAP to be spun and frozen.

Referral laboratory


020 3299 4107


Turnaround time

7-10 Working days

Test indications

Used in the monitoring of tumours of the thyroid medulla

Reference intervals

Male: <11.8pg/mL

Female: <4.8pg/mL

Interferences

Assay

Calcium

Synonyms

Ca2+

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Serum/plasma calcium concentrations are used in the investigation and/or monitoring of calcium metabolism disorders. The laboratory reports plasma/serum total calcium and corrected calcium. The corrected calcium adjusts the calcium concentration according to the serum albumin concentration (due to the binding of calcium ions to albumin).

Reference intervals

1-19 years: 2.13-2.75 mmol/L,

>19 years: 2.30-2.63 mmol/L.

Interferences

Assay

Calcium (urine)

Synonyms

Sample type

Random urine, Universal container

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Used in the investigation of renal stone formation (calculi) and in the investigation of hyper- and hypocalcaemia

Reference intervals

mmol/L

Interferences

Assay

Carbemazepine

Synonyms

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Carbamazepine is an antiepileptic drug for the treatment of epilepsy, trigeminal neuralgia, and simple and complex, partial and generalized convulsive seizures in adults. It is effective as a sole agent in treating the above disorders, but can be used in combination with other antiepileptic drugs. Estimation of carbamazepine levels may be useful when establishing a dosage for new patients, monitoring compliance or assessing for toxicity.

Reference intervals

4-12 mg/L

Interferences

Assay

Carcino embryonic antigen

Synonyms

CEA

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Has been widely used to aid cancer diagnosis, but because CEA may be elevated in a number of non-malignant conditions; elevations must be considered suggestive, but not diagnostic , of cancer. CEA has been most useful for monitoring therapeutic efficiency in patients with adenocarcinoma. High levels are highly suggestive of colorectal cancer

Reference intervals

Interferences

Comments

CEA is not recommended as a screening test for bowel cancer but very occasionally may have a role in the frail elderly in whom cancer is suspected.

Assay

CA 153

Synonyms

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Used to monitor treatment in breast cancer

Reference intervals

<31 U/ml

Interferences

Comment


Assay

Chloride

Synonyms

Cl-, U&E

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Chloride is the principle anion in plasma. Its measurement is useful in the differential diagnosis of fluid balance disorders, and may be useful in the differential diagnosis of acid-base balance via the estimation of an anion gap

Reference intervals

95-108 mmol/L

Interferences

Assay

Cholesterol

Synonyms

CHOL, LIPIDS

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Cholesterol assays are used for screening for atherosclerotic risk and in the diagnosis and treatment of disorders involving elevated cholesterol levels as well as lipid and lipoprotein metabolic disorders. Cholesterol is reported as a lipid profile alongside triglyceride and HDL-cholesterol, as well as calculated LDL-cholesterol and non-HDL cholesterol.

Reference intervals

2-5 mmol/L

Interferences

Comment

A non HDL cholesterol of 2.5 mmol/L is equivalent to an LDL cholesterol of 1.8 mmol/L. Aim for at least a 40% reduction in pre-treatment values.

If >7.5mmol/L, consider discussion with lipid clinic.

Assay

Cholinesterase

Synonyms

Sample type

SST (Gold top)

Test instructions

Referral laboratory

Pathology Sciences Laboratory(Blood Sciences and Bristol Genetics)Southmead HospitalWestbury on TrymBristolBS10 5NB

Tel: 0117 323 6083

Turnaround time

6 weeks

Test indications

Cholinesterase is measured to detect increased sensitivity to succinylcholine and to confirm acute organophosphate poisoning.

Reference intervals

3-9 ku/L

Interferences

Assay

Chromogranin A

Synonyms

Sample type

SST (Gold top)

Test instructions

Referral laboratory


020 3299 4107


Turnaround time

2 weeks

Test indications

Chromagranin A is useful in the monitoring of gastroenteropancreatic tumours, and follow up of patients with liver metastases. Also a useful marker in lung carcinoids and neuroblastomas. Chromagranin A is the major protein within the catecholamine storage vesicles of adrenal medulla. When catecholamines are released, chromagranin is released. It is also released with polypeptide hormones from other endocrine tissues: pancreatic islet cells, enteroendocrine cells, parathyroid chief cells, thyroid parafollicular C cells, and anterior pituitary cells.

Reference intervals

0.35-4.94 mu/L

Interferences

Comment

Chromogranins are often assayed in conjunction with other peptides forming part of the "Gut hormone profile" which includes VIP, gastrin, glucagon, pancreatic polypeptide, somatostatin, chromogranin A and B.

Assay

Chromogranin B

Synonyms

Sample type

EDTA (Purple top)

Test instructions

Referral laboratory


020 3299 4107


Turnaround time

2 Weeks

Test indications

Neuroendocrine tumours

Reference intervals

<150

Interferences

Comment

Chromogranins are often assayed in conjunction with other peptides forming part of the "Gut hormone profile" which includes VIP, gastrin, glucagon, pancreatic polypeptide, somatostatin, chromogranin A and B.

Assay

Clozapine

Synonyms

Sample type

EDTA (Purple top)

Test instructions

2 mL of EDTA whole blood

Referral laboratory

Toxicology Department at King's Hospital

020 3299 5881

[email protected]

King's College HospitalBessemer Wing - 3rd FloorDenmark HillLondon SE5 9RS

Turnaround time

2 working days

Test indications

Clozapine is an atypical antipsychotic used to treat schizophrenia resistant to conventional therapy. Because of the risk of agranulocytosis, white blood cell counts (WBC) are monitored weekly in the early stages of therapy and monthly thereafter. It is recommended that therapy is withheld if the WBC is less than 3,500 mm-3 and abandoned if the WBC falls below 3000 mm-3 or the granulocyte count below 1,500 mm-3. Side-effects of clozapine include lethargy, hypersalivation, constipation and somnolence. There is a risk of hypotension and seizure at higher doses. A single dose of 300-400 mg may be life-threatening in a clozapine naïve subject. Clozapine is metabolised by N-demethylation, hydroxylation and N-oxidation. The N-demethylated metabolite, norclozapine, is present in plasma at similar concentrations to the parent compound, but has a longer plasma half-life. Plasma clozapine concentrations of 0.35 mg/L and above have been associated with a good response, with the risk of convulsions increasing above 1.0 mg/L.

Reference intervals

0.35-0.50 mg/L

Interferences

Assay

Cobalt and Chromium

Synonyms

Sample type


Test instructions

Referral laboratory


020 3299 3008

King's College HospitalBessemer Wing - Top FloorDenmark HillLondon SE5 9RS

Turnaround time

5-7 Days

Test indications

Used in the investigation of chromium or cobalt toxicity

Reference intervals

Cobalt: < 1.7-6.8 nmol/L

Chromium: < 10 nmol/L

Interferences

Assay

C3

Synonyms

Complement, C3/C4

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Lowered values of C3 are indicative of activation, with additional differentiation being made when determining C4 in tandem. If the C4 level is normal, then activation of the alternative route is likely. Depressed values are observed in a number of inflammatory and infectious diseases. Primary causes are systemic lupus erythematosus (SLE), rheumatoid arthritis, subacute bacterial endocarditis, viremia, parasitic infections or bacterial sepsis. A considerable decrease in C3 can be found in patients with partial lipodystrophy or membranoproliferative glomerulonephritis when the C3-nephritis factor is present. Other causes of deficient C3 is a primary Immune deficiency of complement component (although C3 deficiency is extremely rare). More common genetic causes are C2 deficiency (classical) and deficiency of proteins controlling the alternate pathway including factor H, I and x-linked properdin. Further Immunological investigation must be initiated if suspected. As C3 is an acute phase protein, it is produced to an increased extent during inflammatory processes. It is elevated in systemic infections, non-infectious chronic inflammatory conditions (primarily chronic polyarthritis) and physiological states (pregnancy). The elevation rarely exceeds twice the normal value and can mask a reduction in the current consumption.

Reference intervals

<14 days: 0.50-1.21 g/L,

14 days – 1 year: 0.51-1.60 g/L,

1-19 year: 0.83-1.52 g/L,

Female >19 years: 0.82-1.93 g/L

Male > 19 years: 0.82-1.85

Interferences

Assay

C4

Synonyms

Complement C3/C4

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

C4 determinations are indicated when assessing the course of hypocomplement conditions. C4 deficiency is a hallmark for the following conditions: C1 esterase inhibitor deficiency (which controls the classical pathway) known as Hereditary Angioedema (further investigation into C1IN is needed); cryoglobulaemia. (cryoglobulin testing and hepatitis serology may be indicated); and C4 shares an inverse correlation with anti-dsDNA antibodies in SLE.

Reference intervals

<1 year: 0.07-0.30 g/L,

1-19 years: 0.13-0.37 g/L,

Female >19 years: 0.15-0.57 g/L,

Male > 19 years: 0.15-0.53 g/L.

Interferences

Assay

Copper

Synonyms

Cu

Sample type


Test instructions

Referral laboratory


020 3299 3008

King's College HospitalBessemer Wing - Top FloorDenmark HillLondon SE5 9RS

Turnaround time

2-4 Working days

Test indications

Used in the investigation of disorders of copper metabolism

Reference intervals

<5 months: 3-11 umol/L

5-6 months: 3.9-17.3 umol/L

6-11 months: 7.9-20.5 umol/L

>11 months: 12-25 umol/L

Interferences

Assay

Cortisol

Synonyms

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Cortisol is used to investigate the hypothalamic- pituitary-adrenal function. It is commonly used to estimate the physiological response to dynamic function tests (e.g. Synacthen stimulation test or dexamethasone suppression test) when a diagnosis of Cushings disease / syndome or Addisons disease is suspected

Reference intervals

150-600 nmol/L

Interferences

Comment

Random cortisols are not generally useful to exclude Cushing’s or Addison’s

150-600 nmol/l. Reference Range refers to 9am cortisol and assumes established circadian rhythm. In a well patient cortisol levels above 400nmol/L make adrenal insufficiency unlikely. Midnight and post dexamethasone <40nmol/l.

Cortisol increases post synacthen to greater than 480 nmol/L is adequate, between 450-479 nmol/L is equvocal, and less than 450 nmol/L is inadequate.

Assay

Cortisol (Urine)

Synonyms

Sample type

24-hour urine collection in a universal container.

Test instructions

Referral laboratory

Immunochemistry Laboratory at King's College Hospital

020 3299 4130


Turnaround time

3 weeks

Test indications

Used in the investigation of corticoid excess, i.e. Cushings

Reference intervals

<200 nmol/24h

Interferences

Assay

Creatinine

Synonyms

CRT, U&E

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Used in the assessment of renal function, as a marker of glomerular filtration rate. Serum level has an inverse exponential correlation with GFR. Levels may be in the normal range when GFR has halved.

Reference intervals

<14 days: 37-93 umol/L

14 days to 1 year: 27-47 umol/L





Male 15-17 years: 57-92 umol/L

Female 15-17 years: 52-76 umol/L

Male 17-19 years: 61-97 umol/L

Female 17-19 years: 53-78 umol/L

Male >19: 64-111

Female >19: 50-98 umol/L

Interferences

Assay

Creatinine (Urine)

Synonyms

Sample type

Universal white top container

Test instructions

Random urine

Referral laboratory

N/A

Turnaround time

Test indications

Urine creatinine is used either as a marker of urine concentration in the assessment of urinary excretion of compounds (e.g. albumin creatinine ratio, etc.) or the 24hr excretion of creatinine can be used (alongside a serum creatinine taken within the collection period) to estimate glomerular filtration rate (creatinine clearance).

Reference intervals

Interferences

Assay

Creatinine clearance (Urine)

Synonyms

Sample type

24 hour urine, universal container

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Under conditions of normal renal function, creatinine is excreted by glomerular filtration. Creatinine determinations are performed for the diagnosis and monitoring of acute and chronic renal disease as well as for the monitoring of renal dialysis. Creatinine concentrations in urine can be used with serum creatinine to calculate a clearance rate known as a measure of glomerular filtration Rate (GFR).

Reference intervals

80-120 m/L min

Interferences

Assay

Creatine Kinase

Synonyms

CK

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

The determination of CK activity is utilised in the diagnosis and monitoring of myocardial infarction and myopathies such as the progressive Duchenne muscular dystrophy. Following injury to the myocardium, such as occurs with acute myocardial infarction, CK is released from the damaged myocardial cells. Levels may be normal in the first 4-6 hours following infarction. Peak levels seen at 24-48 hours post infarct.

Reference intervals

<15 years: 25-200 u/L,

Female > 15: 25-200 u/L,

Male >15: 40-350 u/L

Interferences

Assay

Cryoglobulins

Synonyms

Cryo

Sample type

SST (Gold top), EDTA Whole blood

Test instructions

Patient must be bled by pathology phlebotomy as the sample must be kept warm as soon as it is taken.

Referral laboratory

Protein Reference Unit

2nd Floor, Jenner Wing

St.George’s Hospital Medical School

Cranmer Terrace

London

SW17 0NH

Turnaround time

10 Days

Test indications

Tests should be requested in patients with cold-induced skin rashes and some patients with renal and joint diseases. A low complement C4 level with or without a rheumatoid factor should also suggest a possible cryoglobulin. Clinically significant cryoglobulins are lost if the sample is allowed to cool below body temperature even for a short period. Once the sample is clotted and is separated it may be handled as any other sample

Reference intervals

Qualitative

Interferences

Assay

CSF Glucose

Synonyms

Sample type

CSF sample, universal container

Test instructions

Referral laboratory

N/A

Turnaround time

Test indications

Used in the investigation of meningitis. CSF Biochemistry investigations include CSF protein and CSF glucose.

Reference intervals

2-4.5 mmol/L

Interferences

Assay

CSF Lactate

Synonyms

Sample type

CSF Sample, universal container

Test instructions

Referral laboratory

N/A

Turnaround time

Test indications


Reference intervals

<8 years: 1.1-1.8 mmol/L

>8 years: 1.2-2.1 mmol/L

Interferences

Assay

CSF Oligoclonal bands

Synonyms

Sample type

CSF Sample and SST (Gold top)

Test instructions

CSF Oligoclonal bands must have accompanying serum sample (collected within 24 hours of the CSF collection)

Referral laboratory


020 3299 4107


Turnaround time

15 Days

Test indications

Used in the investigation of multiple sclerosis

Reference intervals

N/A

Interferences

Assay

CSF Protein

Synonyms

Sample type


Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications


Reference intervals

0.1-0.5 g/L

Interferences

Assay

CSF Xanthrochromia

Synonyms

Sample type


Test instructions

Referral laboratory

N/A

Turnaround time

Test indications

Used in the investigation of subarrachanoid haemorrhage (SAH). CSF Xanthrochromia investigations should only be undertaken in patients suspected of suffering an SAH, where CT scan findings for a cerebral bleed is negative or equivocal. It may remain positive for 2 weeks aftet the event. The LP should only be performed >12 hours after the onset of presenting symptoms .

Reference intervals

N/A

Interferences

Assay

Cyclosporin

Synonyms

Cyclo

Sample type

EDTA (Purple top)

Test instructions

Referral laboratory

Clinical Biochemistry - Blood Sciences at King's College Hospital

020 3299 4126

King's College HospitalBessemer WingDenmark HillLondon SE5 9RS

Turnaround time

7 days

Test indications

Used in the therapeutic drug monitoring of cyclosporin treatment

Reference intervals

No therapeutic range can be quoted due to marked pharmokinetic and drug regime differences between patients

Interferences

Assay

Dehydroepiandrosterone Sulphate

Synonyms

DHEAS, DHAS

Sample type

SST (Gold top)

Test instructions

Referral laboratory


020 3299 4107


Turnaround time

14 Days

Test indications

DHEAS is measured to evaluate adrenal function and certain adrenal tumours, and to investigate the cause of virilisation in girls or early puberty in boys.

Reference intervals

Interferences

Assay

Digoxin

Synonyms

Dig

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Digoxin is a digitalis glycoside that exerts a positive inotropic effect that subsequently increases the contractile response of the myocardial fibers in patients experiencing congestive heart failure. Cardiac glycosides also can produce several electrophysiologic effects that produce negative chronotropic effects on the human heart. These effects tend to slow down and regulate a rapid, irregular beat like that found in patients experiencing cardiac arrhythmias. Estimation of digoxin levels may be useful when establishing a dosage for new patients, monitoring compliance or assessing for toxicity.

Reference intervals

0.5-1 ug/L

Interferences

Assay

Direct bilirubin

Synonyms

DBIL, Conjugated bilirubin

Sample type

SST (Gold top)

Test instructions

N/A

Referral laboratory

N/A

Turnaround time

Test indications

Diseases or conditions which, through hemolytic processes, produce bilirubin faster than the liver can metabolize it, cause the levels of unconjugated (indirect) bilirubin to increase in the circulation. Liver immaturity and several other diseases in which the bilirubin conjugation mechanism is impaired cause similar elevations of circulating unconjugated bilirubin. Bile duct obstruction or damage to hepatocellular structure causes increases in the levels of both conjugated (direct) and unconjugated (indirect) bilirubin in the circulation

Reference intervals

<1 year: 1-5 umol/L




>19 years: 1-4 umol/L

Interferences

Assay

Drug of abuse

Synonyms

DOA

Sample type

Universal container

Test instructions

Random sample

Referral laboratory

Toxicology Department at King's Hospital

020 3299 5881

[email protected]

King's College HospitalBessemer Wing - 3rd FloorDenmark HillLondon SE5 9RS

Turnaround time

1 week

Test indications

Used in the investigation of DOA toxicity. Please note this test is for clinical purposes only

Reference intervals

N/A

Interferences

Assay

Elastase

Synonyms

FELS

Sample type

Faecal sample universal container

Test instructions

Referral laboratory


020 3299 4107


Turnaround time

2 weeks

Test indications

Elastase is a pancreatic enzyme that is not cleaved during its passage through the bowel. In the presence of exocrine pancreatic insufficiency or disorders of exocrine pancreatic function, the elastase secretion is reduced; thus resulting in a decrease of the faecal concentration of this enzyme.

Reference intervals

Normal: 200 - >500 µg E1/g faeces

Moderate to mild exocrine pancreatic insufficiency: 100 – 200 µg E1/g faeces

Severe exocrine pancreatic insufficiency: <100 µg E1/g faeces

Interferences

Assay

Erythropoetin

Synonyms

EPO

Sample type

SST (Gold top)

Test instructions

Referral laboratory


020 3299 4107


Turnaround time

1 week

Test indications

Used in the monitoring of anaemia secondary to renal disease

Reference intervals

5 to 25 U/L

Interferences

Page 36 of 67

Blood Sciences Test User Guide [PD-CHM-TestGuide1] – Version 1

Approved by Steve Short – Review Period: Biennial

Author(s): Samantha Nelson

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