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 reactio |
| 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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