POTASSIUM
(Monotest) BEACON
INTENDED USE:
This reagent kit is intended for the in-vitro quantitative determination of Potassium in Serum.
PRINCIPLE:
Potassium reacts with sodium tetraphenyl boron in a specially prepared buffer to form a colloidal suspension. The amount of turbidity produced is directly proportional to the concentration of potassium in the sample.
CONTENTS:
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Reagent 1: Potassium Reagent
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Reagent 2: Potassium Standard 5 mEq/L
SAMPLE COLLECTION AND PRESERVATION:
Separate serum from the clot as soon as possible as potassium may leach from red blood cells which can elevate results.
REAGENT PREPARATION AND STORAGE:
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All reagents are ready to use.
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Temperature: 25–30°C.
PROCEDURE:
Pipette into cuvettes labeled as Blank (B), Standard (S), and Test (T).
| Addition Sequence | B | S | T |
|---|---|---|---|
| Potassium Reagent | 1.0 ml | 1.0 ml | 1.0 ml |
| Standard | — | 20 µl | — |
| Sample | — | — | 20 µl |
Measure the absorbance of Standard and Test against reagent blank at 630 nm.
CALCULATION:
Concentration of Potassium (mEq/L) = (Abs. T / Abs. S) × 5
NORMAL VALUES:
3.5 – 5.5 mEq/L
Each laboratory should establish its own normal range.
GENERAL SYSTEM PARAMETERS:
Reaction type: End point
Wavelength: 630 nm
Cuvette: 1 cm
Reaction temperature: Room temperature
Zero setting: Reagent blank
Sample volume: 10 µl
Reagent volume: 1.0 ml
Incubation time: 5 mins
Standard concentration: 5 mEq/L
REAGENT SYSTEM STABILITY:
Reagents are stable until the expiration date mentioned on the label.
LINEARITY:
The procedure is linear up to 7 mEq/L.
If values exceed this limit, dilute the sample with distilled water and multiply results with dilution factor.
NOTES:
As potassium is widely distributed, care should be taken to avoid contamination. All glassware should be free from alkali to avoid falsely high values.
BIBLIOGRAPHY:
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Tietz NW, Fundamentals of Clinical Chemistry, W.B. Saunders Co., Philadelphia
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Henry RF et al., Clinical Chemistry Principles and Techniques
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David A. Sacks et al., Tietz Textbook of Clinical Chemistry
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Trinder, P., Ann. Clin. Biochem., 1969 (6: 159)
QUALITY CONTROL:
It is recommended that controls be included in each set of assays.