Creatinine Test Procedure

A serum creatinine test measures the level of creatinine in your blood and provides an estimate of how well your kidneys filter (glomerular filtration rate).

Also Known As:  Creat, Blood Creatinine, Serum Creatinine, 

Panel Tests:  Urea, Blood Urea Nitrogen, Creatinine, Calcium, Phosphorus, Albumin, Magnesium, Total Protien, Electrolytes,

Test Procedure:

Method: Colorimetric, 2 Point Kinetic, “mod. Jaffe”, Increasing reaction

TEST PRINCIPLE:

Creatinine forms a colored orange-red complex in an alkaline picrate solution. The difference in absorbance at fixed times during conversion is proportional to the concentration of creatinine in the sample.

Kit Componants:

• Reagent 1 (R1):
• Reagent 2 (R2):
• Standard: 2.0 mg/dl

REAGENT COMPOSITION

COMPONENTS	CONCENTRATIONS
Reagent 1 (R1)
Sodium Hydroxide	0.2 mol/L
Reagent 2 (R2)
Picric Acid	20 mmol/L

REAGENT PREPARATION:

Substrate Start: The reagents are ready to use.
Sample Start: Mix 4 parts of Reagent 1 with 1 part of Reagent 2. (= Working Reagent)

Sample Preparation:

• Serum: No Need any Preparation
• Urine: Dilute urine 1 + 49 with distelled water.

TEST PARAMETERS
Method	Colorimetric, 2 Point Kinetic, “mod. Jaffe”, Increasing reaction
Wavelength	Hg 492 nm (490 nm – 510 nm)
Temperature	20°C-25°C / 37°C
Sample	Serum, heparin plasma, urine
Linearity	up to 15 mg/dL (1330 µmol/L)
Sensitivity	The lower limit of detection is 0.2 mg/dL

MANUAL TEST PROCEDURE

Bring reagents and samples to room temperature.

Substrate Start :

Pipette into test tubes	Blank	Std/Cal.	Sample
Reagent 1	1000 µl	1000 µl	1000 µl
Sample	–	–	50 µL
Std./Cal.	–	50 µL	–
Mix. Incubate 0 – 5 min., then add:
Reagent 2	250 µL	250 µL	250 µL
Mix. Incubate 1 min. and read A1against reagent blank. Incubate for exactly 2 min. and read A2 against reagent blank. Calculate: ΔA = (A2 – A1) sample or stdandard

Sample Start :

Pipette into test tubes	Blank	Std/Cal.	Sample
Working Reagent	1000 µL	1000 µL	1000 µL
Sample	–	–	50 µL
Std./Cal	–	50 µL	–
Mix. Incubate 1 min. and read A1 against reagent blank. Incubate for exactly 2 min. and read A2 against reagent blank. Calculate: ΔA = (A2 – A1) sample or standard

CALCULATION (light path 1 cm)

The calculated creatinine clearance refers to the average body surface of an adult (1.73 m2).

For serum creatinine (sCr) [mg/dL]:
GFR = 175 x sCr^-1.154 x age^-0.203 x 1.212 (if Afro-American) x 0.742 (if female)
For serum creatinine (sCr) [µmol/L]:
GFR = 30849 x sCr^-1.154 x age^-0.203 x 1.212 (if Afro-American) x 0.742 (if female)

Normal Ranges:

Serum/ Plasma:

• 0.6 – 1.1 mg/dl

Urine:

• 11 – 20 mg/kg/24h

Creatinine Clearance:

• 95 – 160 mL/min/1.73 m2

• Read more about Blood Creatinine
• Read more about Urine Creatinine
• Read more about Creatinine Clearance

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