Blood Bank Fundamentals 1 Immunohematology Building Blocks
Transcript of Blood Bank Fundamentals 1 Immunohematology Building Blocks
Blood Bank Fundamentals 1
Immunohematology
Building Blocks
October 2021
Program Director: Jayanna Slayten, MS, MT(ASCP)SBBcmSupervisor, Indiana University Health Blood BankAnd Adjunct Faculty, University of Texas Medical Branch SBB Program
Faculty Disclosure
• None
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In compliance with ACCME policy,
AABB requires the following
disclosures to the session audience
Objectives• Explain the American Society of Clinical Pathologist (ASCP) SBB and BB
exam requirements
• Review and explain the topics outlined on the ASCP BB/SBB Exam Content
Outline
• Define and relate pertinent information from the ASCP Content Outline that
will be on these exams to aid in preparing for the BB or SBB exam.
• Discover helpful hints for studying for and taking these exams.
• Apply knowledge for interactive question and answer polling session.
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Blood Bank Fundamentals 2021
Session 1 Session 2 Session 3 Session 4
Blood Bank Fundamentals 1: Immunohematology Building Blocks
Blood Bank Fundamentals 2: Immunohematology Methods and Blood Groups
Blood Bank Fundamentals 3: Transfusion Medicine Physiology and Pathophysiology
Blood Bank Fundamentals 4: Donor Collection, Blood Products, Laboratory Management and Blood Bank Quality
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Session 1 Speakers
• Diana Riddle, MS,
MLS(ASCP)CMSBBCM
– University of Texas
Medical Branch
– Galveston, TX
• Kathy Haddaway,
MLS(ASCP)CM SBB
(ASCP)CM
– The Johns
Hopkins
Hospital
– Baltimore, MD
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• LeeAnn Walker,
MEd, MT(ASCP)SBB
– Associate
Professor,
Program Director
– UTMB
SBB/MSTM
Programs
– Galveston, Texas
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Exam Requirements,
Competencies and Content OutlineRequirements, Competencies , Content
Diana Riddle, MS, MLS(ASCP)CMSBBCM
University of Texas Medical Branch
Galveston, TX
ASCP Website Information• Click on: Board of Certification / U. S. Procedures for Certification
Exam
– 38-page booklet – very helpful
• Eligibility assistant
• Scheduling exam / Studying for exam
– Exam content guidelines
– Reading list
– Exam information
• Exam day
• Results and certificate
• US Military
7https://www.ascp.org/content/board-of-certification
Application Information
• Complete and submit application online via credit card
• $240 for BB (Non-refundable)
• $290 for SBB (Non-refundable)
• All correspondence from BOC via email (keep email address current)
• Obtain all necessary documentation before applying
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https://www.ascp.org/content/board-of-certification
Documents Required
Academic education
– Official transcript verifying date of degree
– Evaluation of foreign transcripts
Experience documentation
Accredited program info
– Program director, beginning/ending date, school
number
9https://www.ascp.org/content/board-of-certification
Application Processing• Application processed within 45 business days of
receipt
• Review of documents may take up to 6 weeks
• Admission letter emailed with instructions for
scheduling exam within 3 months
• All exams administered by computer at Pearson
Professional Centers (List of locations click on
Schedule Exam Date / Find a Test Center)• https://home.pearsonvue.com/coronavirus-update
10https://www.ascp.org/content/board-of-certification
SBB Exam RequirementsRoute 1
– Bachelor’s degree with required courses
– Successful completion of CAAHEP-accredited SBB program within last 5 years
Route 2– MT/MLS(ASCP) or BB(ASCP)
– Bachelor’s degree
– 3 years FT BB experience within last 6 years after degree
– Must be attained with pathologist oversight in accredited lab (AABB, CAP, COLA, DNV, TJC, JCI, or under ISO 15189)
11https://www.ascp.org/content/board-of-certification
SBB Exam Requirements
Route 3
– Master’s or doctorate degree
– 3 years FT BB experience in accredited lab within last
6 years after degree
Route 4
– Doctorate degree
– 2 years of post-doctoral fellowship in blood banking
within last 5 years
12https://www.ascp.org/content/board-of-certification
SBB Exam Requirements
Route 5– MT/MLS(ASCP) or BB(ASCP)
– Bachelor’s degree
– 3 years FT experience as an academic educator in clinical blood banking within last 6 years
Route 6– Masters or Doctorate degree
– 3 years FT experience as an academic educator in clinical blood banking within last 6 years
13https://www.ascp.org/content/board-of-certification
BB Exam Requirements
Route 1– MT/MLS(ASCP) and Bachelor’s degree
Route 2– Bachelor’s degree in appropriate field with required
courses
– 1-year full-time BB experience within last 5 years
– Must be attained with pathologist oversight in accredited lab
14https://www.ascp.org/content/board-of-certification
BB Exam Requirements
Route 3– Bachelor’s degree in appropriate field with required
courses
– NAACLS Medical Laboratory Scientist Blood Banking Program within last 5 years
Route 4– Master’s or Doctorate degree
– 6 months FT BB experience in accredited lab within last 5 years after degree
15https://www.ascp.org/content/board-of-certification
BB Exam Requirements
Route 5
– Baccalaureate or post baccalaureate degree in
Medical Lab Science or other appropriate degree
– NAACLS Medical Laboratory Scientist Program
within last 5 years
16https://www.ascp.org/content/board-of-certification
Experience Required
Serologic Testing– ABO and Rh Typing
– Antibody detection and identification
– Crossmatching
– Direct antiglobulin tests
– Tests for other blood group antigens
17https://www.ascp.org/content/board-of-certification
Routine Problem Solving• Transfusion reactions• Immune hemolytic
anemias• Hemolytic disease of the
fetus and newborn (HDFN)
• Rh immune globulin evaluation
• Indications for transfusion
Experience Required (Cont.)
Quality Control / QA
– Reagents
– Equipment
Laboratory Operations
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https://www.ascp.org/content/board-of-certification
Donor Collection, Processing, and Testing
• Donor selection, preparation and collection
• Processing and donor testing
• Component preparation for storage and administration
Certification Level Competencies
• Knowledge of Advanced Principles
• Technical Skills
• Problem Solving and Analytical Decision Making
• Communication
• Teaching and Training Responsibilities
• Supervision and Management
19https://www.ascp.org/content/board-of-certification
Competencies (Questions)
Theoretical - measure skills to:– Apply knowledge
– Calculate results
– Correlate results to disease states
Procedural - measure skills to:– Perform lab techniques
– Evaluate lab data
– Follow QA protocols
20https://www.ascp.org/content/board-of-certification
Competencies (Examples)
Knowledge of Advanced Principles– Ex: Know the underlying principles of lab testing,
validity of results, causes of discrepant results
Technical Skills– Ex: Know the immunohematology lab procedures
(Methods section flash drive at the back of Technical Manual)
– Ex: Test will measure your understanding of quality assurance and ability to monitor QC programs
21https://www.ascp.org/content/board-of-certification
Competencies (Examples)
Problem Solving and Analytical Decision Making
– Ex: Exam may assess your ability to develop and implement plans to correct and prevent problems
Communication– Ex: Exam may assess your ability to communicate lab
data and factors which can influence test results
– Ex: Exam may test your ability to communicate lab policies and operations
22https://www.ascp.org/content/board-of-certification
Competencies (Examples)
Teaching and Training Responsibilities– Ex: Exam may assess your ability to incorporate
principles of educational methodology in the instruction of lab personnel and other health care providers
Supervision and Management– Ex: Exam may assess your ability to give direction
and guidance to technical and support personnel
23https://www.ascp.org/content/board-of-certification
Exam Category Percentages
Subtest BB (%) SBB (%)
Blood Products 15-20 10-15
Blood Group Systems 15-20 15-20
Immunology and Physiology 10-20 15-25
Laboratory Operations 5-10 10-15
Serologic and Molecular Testing 20-25 20-25
Transfusion Practice 15-20 15-20
24https://www.ascp.org/content/board-of-certification
Subtest Descriptions
Subtest Description
Blood Products Donors, processing, storage, blood components, blood component quality control
Blood Group Systems Genetics, biochemistry/antigens, role of blood groups in transfusion
Immunology and Physiology Immunology, physiology, and pathophysiology
Lab Operations Quality assessment/troubleshooting, safety, laboratory mathematics, instrumentation, laboratory administration (SBB only)
Serologic and Molecular Testing
Routine tests, reagents, applications of special tests & reagents, leukocyte/platelet testing, QA
Transfusion Practice Indications for transfusion, component therapy, adverse effects of transfusion, apheresis and extracorporeal circulation, blood administration and patient blood management
25https://www.ascp.org/content/board-of-certification
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Immunology,
Complement and Genetics
Kathy Haddaway, MLS(ASCP)CM SBB (ASCP)CM
The Johns Hopkins Hospital
Baltimore, MD
Immunology• Self vs. Non-self vs. Abnormal self
• Types of immune responses
– Innate (nonspecific, present at birth, immediate action)
• Physical barriers (skin, cilia, cough & sneeze reflex, mucus membranes)
• Biochemical barriers (mucus, saliva, tears, sweat, pH)
• Cellular (Phagocytic cells)
• Humoral (complement, cytokines)
• Inflammation (edema, vasodilation, cell migration)
– Adaptive/Acquired (specific, memory, primary vs. secondary)• Cellular (lymphocytes & APCs)
• Humoral (antibodies)
Harmening, D.M. (2012). Modern Blood Banking and Transfusion Practices (6th ed.). Philadelphia: F.A. Davis Company. Chapter 3 27
Immunology• Organs of the Immune System
– Primary (Thymus & Bone Marrow)
• Site of differentiation & maturation of T cells & B cells
– Secondary (Lymph nodes, Spleen, MALT)
• Site of cell function
• Cells of the Immune System
– Hematopoietic Stem Cells (CD34) → self-renewal & differentiation
– T Helper Cells (CD4) → MHC II → stimulate B & cytotoxic T cells
– T Cytotoxic Cells (CD8) → MHC I → destroy tumor & infected cells
– B cells (CD20) → Plasma cell → Make antibodies
– NK cells (CD56) → Lyse tumor & virally infected cells
– APCs (Monocytes, Macrophages, Dendritic cells…) → Phagocytize
Harmening, D.M. (2012). Modern Blood Banking and Transfusion Practices (6th ed.). Philadelphia: F.A. Davis Company. Chapter 3 28
Immunology
Harmening, D.M. (2012). Modern Blood Banking and Transfusion Practices (6th ed.). Philadelphia: F.A. Davis Company. Chapter 3
• Antigen Characteristics that affect immune response
– Size (larger) & Density (more dense)
– Charge
– Accessibility (ability of immune system to see it)
– Solubility (More soluble)
– Digestibility
– Degree of Foreignness• Chemical composition
• Complexity
• Conformation
• Relative Immunogenicity:
– D > K > c > E > k > e > Fya < C < Jka < S < Jkb < s
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Immunology
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 8
• Antibody (Immunoglobulins) Characteristics
– Two Heavy chains & two light chains
– Variable (Idiotype), Constant (Allotype) & Hinge region
– Fc domain & 2 Fab domain (papain)
Isotype IgM IgG IgA IgE IgD
Structure Pentamer MonomerMonomer or
DimerMonomer Monomer
Activate
Complement
Yes,
1 IgM
Yes,
2 IgG
Alternative
pathwayNo No
Cross Placenta NoYes,
IgG2 weaklyNo No No
Subclasses No Yes, 1-4 Yes, 1-2 No No
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Immunology
Muylle, L. (1995). The role of cytokines in blood transfusion reactions. Blood reviews,9, 77-83.
• Cytokines Types:
• Lymphokines – made by lymphocytes
• Monokines – made by monocytes & macrophages
• Chemokines – increase motility and migration of WBCs
• Interleukins – made by WBCs to act on other WBCs
– Effect:• Autocrine – affects itself
• Paracrine – affects cells in close proximity
• Endocrine – affects systemic activity
– Function:• Growth factor – G-CSF, GM-CSF, M-CSF
• HTR – IL-1, IL-6, IL-8, TNF-α, MCP-1
• FNHTR – IL-1, IL-6, IL-8, TNF-α
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Immunology
Stevens, C.D. and Miller, L.E. (2017). Clinical Immunology and Serology: A Laboratory Perspective (4th ed.). Philadelphia: F.A. Davis Company. Chapter 14
• Hypersensitivity
– Type I – Allergic
• IgE causes mast cells to release histamine
• Rash, urticaria, anaphylaxis
– Type II – Cytotoxic
• Ag-Ab mediated
• HDFN, Autoimmune disease
– Type III – Immune Complex
• Soluble Ag-Ab complexes
• Drug Induced hemolytic anemia
– Type IV – Cell Mediated
• Antigen stimulates specific T cell mediated cellular damage
• GVHD, Poison Ivy, Allograft rejection
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Immunology
Stevens, C.D. and Miller, L.E. (2017). Clinical Immunology and Serology: A Laboratory Perspective (4th ed.). Philadelphia: F.A. Davis Company. Chapter 15 & 19
• Immune-mediated diseases
– Immunodeficiency diseases
• Recurrent infections, risk of TA-GVHD
– Autoimmune diseases
• Antibodies form to self, positive DATs
– Gammopathies
• Abnormal production of Ig, Rouleaux
– HDFN• Maternal antibody destruction of fetal RBC’s
• Immunotherapies
– IVIg, RhIg, Monoclonal antibody therapy
• Serologic test interference
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Complement
Stevens, C.D. and Miller, L.E. (2017). Clinical Immunology and Serology: A Laboratory Perspective (4th ed.). Philadelphia: F.A. Davis Company. Chapter 14
• Role:– Lysis of cells, bacteria, and enveloped viruses
– Opsonization of foreign material to enhance phagocytosis
– Generation of minor proteins that mediate inflammation
• Pathways:– Classical – activated by 1 IgM or 2 IgG
– Alternative – activated by cell walls (bacteria, viruses, etc)
– Lectin – activated by mannose binding lectin on microbial cell walls
• Control of complement activation– Decay Accelerating Factor (DAF) – Cromer blood group
– Complement receptor 1 (CR1)
• Deficiencies of complement components– PNH, SLE, RA
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Blood Group Genetics
Kathy Haddaway, MLS(ASCP)CM SBB (ASCP)CM
The Johns Hopkins Hospital
Baltimore, MD
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Mendel’s Principles• Random Segregation
– Distinct units (genes) inherited
– One from each parent
– Random
• Independent Assortment
– Genes inherited independently if carried on different chromosomes
– Combinations of genes are not dependent on other genes (Exception: linkage)
• Linkage Disequilibrium
– Genes on closely linked loci are inherited together as a haplotype
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9 36
Definitions• Allele/ Locus/ Antithetical
• Cis/Trans
• Lyonization
• Genotype/Phenotype
• Dominant/Recessive
• Dosage
• Haplotype
• Homozygous/Heterozygous/Hemizygous
• Suppressor Gene
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9 37
• Allele
– JK*01 or JK*A
– N demotes null (RHD*01N.01 – D negative)
• Genotype/haplotype
– JK*01/JK*01 or JK*A/JK*A
• Phenotype
– JK:1,-2 (traditionally Jk(a+b-)
• Antigen
– Jk1 or 0009001 or 9.1 (traditionally Jka)
ISBT Terminology
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9 38
Pedigree Analysis - Genetic Symbols• See Technical Manual...
Not affected Affected Heterozygote/
Carrier
Female
Male
X-linked
recessive
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9 39
Pedigree Analysis - Genetic Symbols• See Technical Manual...
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Mating
Consanguineous Mating
Monozygotic Twins
Dizygotic Twins
Proband
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
Autosomal Dominant
41Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
• Trait appears in every generation (no skipping)• Trait is transmitted by an affected person to half
his children• Unaffected persons do NOT transmit the trait to
their children• Equally likely in both males and females
Autosomal Recessive
42Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
• Trait appears in siblings, not in their parents or offspring (not in every generation)
• One-fourth of sibs of propositus are affected
• Parents of affected child may be consanguineous
• Equally likely in both males and females
Sex-Linked Dominant
43Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
• Affected Males (XY) transmit the trait to ALLdaughters and to NO sons
• Affected Females (heterozygous XX) transmit to half of their children of either sex
• Homozygous females (XX) transmit to ALL of their children
• Distinguished from autosomal dominant only by offspring of affected males
Sex-Linked Recessive
44Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
• Incidence of trait is much higher in males than females
• Trait passed from affected man through all daughters to half of their sons
• Trait is never transmitted directly from father to son
• Trait may be transmitted through a series of female carriers
Y-Linked
45Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
• Resembles X-linked• Trait is transmitted only from father to son,
never to daughter• ALL sons will be affected
Blood Group Chromosomes
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Chromosome Blood Group
1 Rh, Duffy, Scianna, Cromer, Knops, Vel
2 Gerbich, Lan
3 Globoside
4 MNS, JR
6 Chido/Rodgers, I, RHAG, HLA, Augustine
7 Kell, Yt, Colton
9 ABO, Gill, FORS
11 Indian, Raph, CD59
12 Dombrock
15 JMH
17 Diego
18 Kidd
19 Lutheran, Lewis, LW, H, Ok,
22 P1Pk
X Xg, Kx
Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
Population Genetics• Gene and phenotype frequencies are based on
probability
• To determine the frequency of any two (or more) unrelated traits, simply multiply the frequencies of each trait.
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Populationsample
f = 2%So, f = 2%
Jorde, L.B., Carey, J.C., Bamshad, M.J., & White, R.L. Medical Genetics, 4th ed. St. Louis, MO: Mosby, 2009. Chapter 3
Population Genetics• Gene frequency changes:
– Selection - One gene makes organism more efficient in reproduction, gene
increases in frequency
• Sickle Cell Disease
– Genetic drift – random change in gene frequency by chance, seen more in small
populations
• Ellis–van Creveld syndrome in PA Amish
– Migration/Gene flow – movement of population and breeding with other
populations
– Mutation – change in genetic material
– Meiotic drive – more genes for one allele produced during meiosis
48Jorde, L.B., Carey, J.C., Bamshad, M.J., & White, R.L. Medical Genetics, 4th ed. St. Louis, MO: Mosby, 2009. Chapter 3
Population Genetics
• Hardy/Weinberg Equation
• Basic Formula: (a + b)2
– Two heterozygous parents: (Aa x Aa)
– Offspring: 1 AA + 2 Aa + 1aa
Mom Aa
AA Aa Dad Aa Aa aa
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Hardy-Weinberg Equation
• Gene Frequencies
p and q (2 allele)
p, q, and r (3 allele)
• Phenotype – 2 allelep2 and q2 (Homozygous)
2pq (Heterozygous)
– 3 allelep2 , q2, r2 (Homozygous)
2pq, 2pr, 2qr (Heterozygous)
50Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
Mom Aa
AA Aa Dad Aa Aa aa
Hardy-Weinberg Equation
• Generalized equation:– (p + q)2 = p2 + 2pq + q2 = 1
– For 2 alleles (gene frequencies): • p + q = 1 or q = 1 - p
– Expanded (phenotype frequencies): • p2 + 2p(1 - p) + (1 - p)2 = 1
51Fung, M.K. et al. (Eds.). (2017). Technical Manual (19th ed.). Bethesda, MD: AABB Publications. Chapter 9
Assumption for Hardy-Weinberg Equation
• Individuals of each genotype must be as reproductively
fit as individuals of any other genotype (no infertility or
mortality)
• Population must have large number of individuals
• Random mating must occur
• No mutations
• No migration
52Harmening, D.M. Modern Blood Banking and Transfusion Practices, 6th ed. Philadelphia: F.A. Davis Company, 2012. Chapter 2
• In a given population, 84% of individuals are D positive (D) and 16% are D negative (d)– Phenotype expression:
• DD = p2
• Dd = 2pq
• dd = q2 = 0.16 D negative = 16%
• p2 + 2pq + q2 = 1
– Allele frequency:• p + q = 1
• q = square root of q2
– Square root of 0.16 = 0.4
• p + q = p + 0.4 = 1
– p = 1 – 0.4 = 0.6
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Hardy-Weinberg Equation
Therefore:DD = p2 = (0.6)2 = 0.36Dd = 2pq = (2)(0.6)(0.4) =0.48dd = q2 = (0.4)2 = 0.16
1.00
D positive = 84%
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The Math of the Blood Bank
LeeAnn Walker, MEd, MT(ASCP)SBB
Associate Professor, Program Director
UTMB SBB/MSTM Programs
Galveston, Texas
Formulas…and why we use them…
• Making reagents
• Validating instruments or methods
• FTEs and staffing / cost analysis
• Predicting # of units to screen for antibody
patients
• Blood product QC
• Calculating:
– total blood/plasma volume
– product dosage
– transfusion effectiveness
– special donors
• Scientific Notation (x 106)
– Add, subtract, multiply, & divide
• Conversion Factors
– Weight:
• 1 lb = 0.45 kg
• 1 kg = 2.2 lbs
– Length:
• 1 in = 2.54 cm
• 1 cm = 0.39 in
– Volume:
• 1 qt = 0.95 L
• 1 L = 1.06 qt
• Remember the units!
There’s a LOT of math in our blood bank world!
Doucette, L. J. Mathematics for the Clinical Laboratory, 3rd ed. Philadelphia: W.B. Saunders Company, 2016.
Formulas…and why we use them
• Reagent Preparation
– Prepare & modify solutions
• % Weight/Volume (w/v) - Grams of solute in 100 mL of solution
• % Weight/Weight (w/w) - Grams of solute in 100 grams of solution
• % Volume/Volume (v/v) - Milliliters of solute in 100 mL of solution
– Adjusting concentration• Set up a ratio – V1 x C1 = V2 x C2
– Serial or compound dilutions
• Multiply individual dilutions Technical Manual: Method 1-4Technical Manual: Method 1-5, 1-6, 1-7
• Basic measures of central tendency – LOTS of uses!
– Mean – arithmetic average –
– Median – middle value of a group of data
– Mode – value that occurs most frequently
– Range – difference between the highest and lowest value in
the data set.
– Midrange – Add highest + lowest ÷ 2
– Standard Deviation – square root of the variance
Formulas…and why we use them
Given the following set of hemoglobin values, determine the
mean, median, mode, range and midrange. All values are g/dL.
10.2
10.5
10.6
12.2
12.8
12.8
13.1
13.2
14.1
• First thing to do is to total the values.
– Number of values = 9
– Total of values = 109.5
– Determine mean = 12.2
• Then put the values in numerical order.
– Determine median, mode, range and mid-range.
13.2
12.8
10.2
10.6
13.1
12.8
12.2
14.1
10.5
Given the following set of hemoglobin values, determine the
mean, median, mode, range and midrange. All values are g/dL.
13.2
12.8
10.2
10.6
13.1
12.8
12.2
14.1
10.5
10.2
10.5
10.6
12.2
12.8
12.8
13.1
13.2
14.1
• Total of values = 109.5
• Mean = 109.5 / 9 = 12.2
• Median (# in the middle) = 12.8
• Mode (# that occurs most often) = 12.8
• Range (highest – lowest) = 14.1 – 10.2
= 3.9
• Mid-range [(highest + lowest)/2] =
– 14.1 + 10.2 = 24.3 / 2 = 12.15 or 12.2
Formulas…and why we use them
• Sensitivity & Specificity
– Frequently used in research and validation procedures.
– Sensitivity looks at True Positives (TP): TP / (TP + FN)
– Specificity looks at True Negatives (TN): TN / (TN + FP)
– An acceptable sensitivity & specificity will be determined
by the test or by the laboratory requirements.
• Positive Predictive Value (PPV): TP / (TP + FP)
• Negative Predictive Value (NPV): TN / (TN + FN)
• Calculating FTEs and staffing
– Need to know workload and productive hours
• 2080 paid hours / yr (52 weeks x 40 hrs)
• Exclude PTO/holidays
• 75% productivity assumption unless given otherwise– 45 min/hr
• Cost analysis
– Evaluating methods and instruments
– Include salary cost if applicable
Formulas…and why we use them
Formulas…and why we use them…
• Genetics…
– Hardy-Weinberg
• Determining gene and phenotype frequencies in a population.
– Calculating units for screening
• Remember that you might be given antigen frequencies.
• If not specified, you may also need to include ABO
compatibility in calculations.
• Use Caucasian or general frequencies unless question
specifies otherwise.
Formulas…and why we use them…• Blood product manipulations
– Factor VIII or fibrinogen yield in Cryo
– Platelet yield – whole blood or apheresis
– Extracorporeal volume on apheresis donor or patient
– Adjusting hematocrit
• Product dosage
• Product effectiveness
• Half-Life
– FVIII – approximately 8-12 hrs
– IgG – 23-25 days
• RhIg and exchange transfusions
Lab Math – Blood Volume• To determine Total Blood Volume, Plasma Volume or Red Cell Volume:
Technical Manual: Appendix 5
Premature Term Infant Adult Male Adult Female
Total Blood Volume (mL/kg)
108 87 66 60
If hematocrit is known, calculate PV or RCV.Example: 175 lb. male with hct 44% ( HCT is % of RC, so % of plasma is 1 - hct).
• Convert lb to kg: 175 lb / 2.2 = 79.5 kg• Multiply kg by TBV/kg: 79.5 kg x 66 mL/kg = 5250 mL TBV• For RCV, multiple TBV by hct: 5250 mL x 0.44 = 2310 mL red cells• For PV, multiply TBV by % of plasma: 5250 mL x 0.56 = 2940 mL plasma
Lab Math – Product Dosing• RBCs
– RBCs decrease at a rate of ~1% of per day
– One unit of RBCs increase Hgb by 1 g/dl & Hct by 3%
– 1ml of RBCs = 1 mg of iron
• Plasma
– One unit of plasma increases coag factors by ~10%
• Platelets
– One WB derived plt increases 5,000-10,000/μl in an adult
– One apheresis plt increases 50,000-60,000/μl in an adult
– One WB derived plt increases 75,000-100,000/μl in a term infant
65
Harmening, D.M. Modern Blood Banking and Transfusion Practices, 7th ed. Philadelphia: F.A. Davis Company, 2019. Chapter 16
Lab Math – Product Dosing (Cryo)
For FVIII dosing:
1. Determine desired increment of
FVIII (IU/ml)
– (desired FVIII – initial FVIII)
2. Desired FVIII (IU)
– PV (mL) x desired increment
FVIII (IU/ml)
3. FVIII in Cryo
– Assume 80 IU FVIII per bag of
cryo
4. Desired FVIII (IU)/80 IU = # of bags
For Fibrinogen dosing:
1. Determine desired increment of
Fibrinogen (mg/mL)
– (desired fibrinogen – initial fibrinogen)
2. Desired Fibrinogen (mg/mL)
– PV (mL) x desired increment
Fibrinogen (mg/mL)
3. Fibrinogen in Cryo
– Assume 150 mg per bag of cryo
4. Desired Fibrinogen (mg)/ 150 mg = # of
bags
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For either FVIII or for Fibrinogen: Determine plasma volume
A severe hemophiliac is scheduled for surgery tomorrow. His physician wants to increase his Factor VIII level to 75% before the procedure. His hematocrit is 40% and his plasma volume is 3000 mL. How many bags of cryoprecipitate should be given?
• Number of bags =
– PV x [Desired activity (%) – Current activity (%)] x PV / 80
• Severe hemophiliac has 0 FVIII activity.
• 3000 mL x (0.75 - 0) = 2250 IU FVIII
• 2250 IU / 80 IU = 28 bags of cryo
Lab Math – Product Yield• Percent Yield (Cryo or WB platelets) =
amount x mL final product x 100%
amount x mL original product
Lab Math – Neonatal exchange transfusion• Volume of WB to transfuse (mL) =
• Infant’s TBV (mL) x # of exchanges = Total vol (mL) for exchange
• Volume (wt) of RBC unit x Hct = RBC volume available
• RBC volume ÷ desired Hct = Total WB volume from that unit• Total WB volume from unit – volume of existing unit = volume of
plasma to add
NOTE: Specific Gravity of RBC is ~1.06, so to determine mL:
• Wt (g) / 1.06 = Vol (mL)
Lab Math – Calculating Fetal Maternal
Hemorrhage & RhIG• Volume Fetal maternal hemorrhage (ml)
# fetal cells counted x maternal blood volume x maternal blood volume
# maternal cells counted
Or
% fetal cells x 50 (50 = factor for average maternal blood volume of 5000 mL)
• RhIg dose (vials) =Volume FMH whole blood (ml) / 30 ml/vial
Volume FMH pRBC (ml) / 15 ml/vial
– Round up or down + 1 vial
Lab Math - Additional Formulas:
• Relative Centrifugal Force 11.17(r)(n/1000)2
• r = radius in cm
• n = rotor speed in rpm
• Relative Risk (RR) HLA disease association(% patients with HLA antigen) x (% controls without HLA antigen)
(% controls with HLA antigen) x (% patients without HLA antigen)
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Cohn, CS. et al. (Eds.). (2020). Technical Manual, 20th ed. Bethesda, MD: AABB Publications. Chapter 16
Remember the Units!!• Other quick facts…
– Maximum volume of blood to draw from a donor: 10.5 mL/kg
• Or Donor weight (lbs) x 450 mL
110 lbs
– Maximum extracorporeal volume for apheresis: 15% of TBV
– Scientific Notation
• To add or subtract, the exponent must be the same; then
add or subtract the mantissas (the number part).
• To multiply, multiply the mantissas and add the exponents.
• To divide, divide the mantissas and subtract the exponents.
References•Cohn, Claudia, et al, ed. Technical Manual, 20th ed. Bethesda, MD: AABB, 2020.
•Fridey, JL, Kasprisin, CA, Chambers, LA, Rudmann, SV. Numbers for blood bankers. Bethesda, MD: American Association of Blood Banks, 1995.
•Doucette, L. J. Mathematics for the Clinical Laboratory, 2nd ed. Philadelphia: W.B. Saunders Company, 2010.
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Test Your Blood Bank Knowledge
Q and A Session
BB Fundamentals Session 1
BBF1. Q0 How many years
experience are required to sit for the
BB exam?
• 3 years in the last 10 years
• 1 year in the last 5 years
• 3 years in the last 6 years
• No experience required
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BBF.1 Q1: A transfusion reaction was reported for a patient who received a
unit of plasma earlier today. The lab results are as follows:
Symptoms: hives, urticarial, pruritis
Pre-temp: 37.0oC Post temp: 37.2oC
Pre BP: 120/78 Post BP: 115/75
Pre Hgb: 12.0 g/dL Post Hgb: 11.8 g/dL
Urine: clear, yellow; Hgb – negative; 0 RBC’s/hpf
What type of hypersensitivity reaction is this patient experiencing?
a. Type 1
b. Type 2
c. Type 3
d. Type 4
75
BBF Q2 Given the pedigree below, what type of inheritance is the trait?
A) Autosomal Dominant, b) Autosomal Recessive, c) X Linked
Dominant, d) X linked recessive
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A. 790
B. 620
C. 520
D. 455
BBF Q3 Male pattern baldness is controlled by a recessive gene (b), while non-baldness is coded by a dominant allele (B). Out of 1000 random men, 380 had a full head of hair. How many would be carriers of the baldness gene?
BBF.1 Q4 A 2.5 lb premature neonate requires an exchange transfusion due to anti-c HDFN. How much reconstituted whole blood is needed for a 2-volume exchange?
A. 240 mL
B. 220 mL
C. 105 mL
D. 95 mL
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Thank You for Participating
Please Continue with us with the next
BB Fundamentals Course
Blood Bank Fundamentals 2: Immunohematology
Methods and Blood Groups