Creatinin Estimation

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OBJECT: To estimate the conc. Of creatinin in a given serum sample

REAGENTS : R1 -Sodium hydroxide R2 -Picric acid Standard: 2mg/dl (177 micromole/l) Mix 4parts of R1 with 1part of R2, the mixture is known as monoreagent.

PRINCIPLE: Creatinin is a waste product excreted by the kidneys mainly by glomerular filtration. The concentration of creatinin in plasma of a healthy individual is fairly constant, independent from water intake, exercise and rate of urine formation. Therefore increased plasma creatinin values always indicate decreased excretion I.e., impaired kidney function.

Creatinin forms a orange-red complex in an alkaline solution. The difference in absorbance at fixed time intervals during conversion is proportional to the conc. Of creatinin in the sample.

creatinin + picric acid -------→ creatinin picrate complex

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PROCEDURE:

Wavelength: 492 nm Optical path: 1 cm Temperature: 20-25 C Measurement: Against reagent blank

BLANK SAMPLE

SAMPLE

___

100 micro

STANDARD ___

liter STANDARD DISTILLED WATER MONOREAGENT

___ 100 micro liter 2 ml

___

100 micro liter

___

___

2 ml

2 ml

Mix and read absorbance A1 after one minute. Read absorbance A2 after two minutes.

∆A = [ (A2 – A1) sample or standard ] - [(A2 – A1) blank ]

CALCULATIONS:

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Creatinin conc. = ∆A sample / ∆A standard

X conc. Of standard

RESULT: The conc. Of creatinin in the given sample is found out to be -------------- mg/dl

INTERPRETATION: