QUICK POINTS The flame photometer burns the patient's ...€¦ · flame photometer burns the...

Chapter 13; Flame Photometer

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QUICK POINTS

• The flame photometer commonly measures three

elements, sodium, potassium and lithium levels

within a patient's blood or urine. Other elements may

also be measured.

• The flame photometer burns the patient's serum or

urine which produces different flame colors,

dependent upon the element. The color and intensity

of the color is measured, producing the

measurement.

• Abnormal levels of sodium and potassium may

indicate kidney problems.

• There are four basic parts to a flame photometer

which are the burner assembly, a nebulizer/mixing

chamber, an optical system and a photodetector.

• Lithium is commonly used as a control standard to

compensate for fluctuations in flame temperature

and aspiration rates, ensuring accurate readings.

• Common issues the biomed will experience with the

flame photometer are burner/flame issues.

• Specific to the flame photometer, the biomed verifies

element measurement accuracy, pump accuracy and

performs routine maintenance.


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CHALLENGE QUESTIONS

1. What is the main purpose of a lab flame photometer?

2. How is the patient’s sample measured?

3. What may abnormal levels of sodium and potassium

indicate?

4. How does a flame photometer work?

5. What is the flame window used for?

6. What are four basic parts of a flame photometer?

7. What can cause inaccurate readings?

8. If there is an issue with the flame photometer, what

is the first thing a biomed should check?

9. How does the flame photometer compensate for

fluctuations in flame temperature and aspiration

rates?

10. What is the most common issues the biomed will

experience with the flame photometer?

11. Outline the specific tests a biomed performs on the

flame photometer?


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CLINICAL INFORMATION

What is a flame photometer?

The laboratory’s chemistry department uses a

flame photometer to commonly measure three elements,

sodium, potassium and lithium levels within a patient's blood

or urine. Other measurements may also be available. The

flame photometer burns the patient's serum or urine in a

flame, which produces different flame colors, dependent

upon the sodium, potassium or lithium levels. Sodium emits

a wavelength of 5890λ which is yellow in color when

burned, potassium emits a wavelength of 4047λ which is

violet in color when burned and lithium emits a wavelength

of 6708λ which is red in color when burned.

Why measure sodium and potassium?

Abnormal levels of sodium and potassium may

indicate kidney problems. Normal values found in a patient's

urine range between 25 to 100 mEq/24h of potassium and

100 to 260 mEq/24h of sodium. Normal blood values are 3.5

to 5.0 mEq/L of potassium and 135 to 145 mEq/L of sodium.


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How does the flame photometer work?

A flame photometer consists of four basic

components:

1. A burner: A burner provides a flame.

2. A nebulizer and mixing chamber: transports the

patient sample and standard to the flame at a

constant rate.

3. Optical system: A common design for the optical

system includes a convex mirror, lens and filter.

The convex mirror transmits light emitted from

the flame to the lens. The convex lens focuses the

light to a point towards the filters. The filters

block other wavelengths other than the one being

measured.

4. Photo detector: The photodetector detects the

emitted light from the flame and measures its

intensity. It then converts the detected light to an

electrical signal, which is proportional to the

intensity of light.


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Flame photometers measure sodium (Na),

potassium (K) and lithium (Li) levels. The flame photometer

burns the patient's serum or urine in a flame, which produces

different flame colors, dependent upon if it is sodium,

potassium or lithium within the flame. When elements are

burned within a flame, they each emit a specific wavelength

of light which varies in intensity, dependent upon

concentration. When the flame photometer measures each

specific element’s wavelength, it uses a filter to block all

other wavelengths or colors. Fluctuations in flame

temperature and concentration (aspiration) can affect

accuracy of the readings. To obtain an accurate value, the

element measured is compared to a standard. When the

flame photometer burns the patient’s urine or serum sample,

lithium is added as the standard. Because lithium is a known

concentration, the sodium and potassium intensity levels are

measured against it, which compensates for fluctuations in

flame temperature and aspiration rates. The flame

photometer can used other standards including potassium or

cesium, dependent upon the manufacturer's design. Sodium

emits a wavelength of 5890λ (yellow), potassium emits a

wavelength of 4047λ (violet) and lithium emits a wavelength

of 6708λ (red) when burned.

How is the patient’s sample measured?

A small tube aspirates or sucks the sample

towards the flame and the measurements are displayed. This

small tube is placed in deionized water, used to clean the

flame photometer, making it ready for the next sample.


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COMMON FEATURES of a FLAME PHOTOMETER

Calibrate:

The calibration button allows the user to start the

process of a calibration or make a calibration check. Specific

standards are used to check the accuracy of each element.

The calibration routine may be a manual process or totally

automated.

Gas adjustments:

The flame may be adjusted manually using gas

control(s) or fully automated.

Flame window:

A window allows the user to see the flame and see

its color, while burning elements. The flame should be

colorless if burning deionized water.

Filter selection:

A specific filter is selected to acquire the specific

element such as sodium, potassium, etc. Alternatively, the

flame photometer may be automated and make all

measurements simultaneously, without user intervention.

Zero adjustment:

This adjustment is used to zero the value, prior to

making a measurement. Alternatively, the zero adjustment

may be automated.


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HOW TO TEST/PM THE FLAME PHOTOMETER

Always refer to the manufacturer's service manual for a

complete recommended PM guideline. Following is a

generic guideline only!

Perform a visual inspection:

• Ensure the overall flame photometer has no obvious

issues such as a broken case, etc. Inspect the burner

for issues and ensure it is clean.

Ensure all user controls are operational:

• Ensure all the user controls are functioning during

your tests. A biomed will often find user controls not

working during their testing. If a button/control is not

working, repair it prior to placing the flame

photometer back into service.

Verify the element accuracy:

• The biomed verifies accuracy of the sodium,

potassium and lithium levels by using control

standards with known values. Accuracy checks are

usually done using high, low and normal values.

• If the flame photometer measures other elements,

control standards are also used to check their

accuracy.

• If the accuracy is not within the manufacturer’s

specifications the biomed must either calibrate or

repair the flame photometer.


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Verify aspiration pump accuracy:

• The flame photometer aspirates a very low volume

of the element. The volume accuracy is vital for

accurate results. The biomed verifies aspiration

pump accuracy as per the manufacture testing

procedure.

Perform routine maintenance:

• The manufacturer will recommend cleaning and/or

replacement of seals. gaskets, tubing, etc. This may

occur a few times per year.

• Always follow the manufacturer’s recommended

procedures.

Always perform a final functional check:

• As a final test, the biomed should do a quick

operational test to ensure proper operation, prior to

placing it back into service.

• All operation, controls and alarms should operate as

per the manufacturer's design.

Ensure your documentation is accurate:

• All repairs and performance tests need to be

documented so that they can be retrieved at any time.

• This documentation should include all parts used for

repair and that all the above tests showing the

equipment is within manufacturers and local

authorities acceptable limits.

• These documents may be used legally to validate the

proper maintenance was performed by the biomed.

Ensure your documentation is accurate!


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What do I do if any of my checks fail?

• If any device maintained by the Biomed fails a

functional test and/or electrical safety, it is the

biomed's responsibility to pull it out of service!

• Failure means a patient safety issue exists!

• Fix the issues prior to placing the flame photometer

back into service!


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QUICK SERVICE TIPS

WARNING:

• The burner assembly it very hot. Be careful while

servicing the burner assembly!

No flame:

• If there is an issue with the flame photometer, the

first thing to verify is the presence of a flame. The

flame photometer must have a flame to operate.

Many issues can cause the flame to not light. Two

common issues are a lack of gas supply or a problem

with the flame ignition switch. Ensure the gas supply

is available and flowing to the flame photometer.

Ensure the burner assembly is clean and no

obstructions are found. It is not uncommon for the

entire burner unit to be replaced, if there are issues

with it. Always refer to the manufacturer’s guidelines

for testing the burner assembly.


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CHALLENGE ANSWERS

1. The main purpose of a flame photometer is to

measure three elements, sodium, potassium and

lithium levels within a patient's blood or urine. Other

elements may also be measured.

2. The patient’s sample is measured through a small

tube that aspirates or sucks the sample towards the

flame, where the measurements are made.

3. Abnormal levels of sodium and potassium may

indicate kidney problems.

4. A flame photometer burns the patient's serum or

urine which produces different flame colors,

dependent upon the element. The color and intensity

of the color is measured, producing a value.

5. The flame window allows the user to see the

flame’s color, while burning elements. The flame

should be colorless if burning deionized water.

6. The four basic parts to a flame photometer are the

burner assembly, a nebulizer/mixing chamber, an

optical system and a photodetector.

7. Inaccurate readings can be caused by fluctuations in

flame temperature and concentration (or aspiration).

8. The first thing a biomed should check is the

presence of a flame.

9. The flame photometer compensates by using a

standard (often lithium). The sodium and potassium

intensity levels are measured against it, which

compensates for fluctuations in flame temperature

and aspiration rates.

10. The most common issue the biomed will experience

with the flame photometer are burner/flame issues.


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11. Specific to the flame photometer, the biomed

verifies element measurement accuracy, pump

accuracy and performs routine maintenance.

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