Creatinine (Cr)

The Creatinine (Cr) assay evaluates the level of creatinine, a waste product generated by muscle metabolism, in the bloodstream. This test is crucial for assessing hydration status and kidney function, as the kidneys filter creatinine from the blood. People typically undergo this test as part of routine health check-ups, especially if they have risk factors for kidney disease, such as high blood pressure or diabetes. Elevated levels may signal kidney dysfunction or impaired filtration, while low levels could indicate reduced muscle mass or rare metabolic disorders.

Sample Requirements:
Gold SST Tube

Stability:
Serum: 7 days 4-25°C

Turnaround Time:
2 hours

Critical Value:
Above 354 umol/L (200 umol/L if <16yo)

Assay Interferences:
Recovery within ± 10 %
Icterus: < 10% or 14umol/L up to 40mg/dL or 684umol/L bilirubin

Haemolysis: < 3% or 4.2umol/L up to 5g/L haemoglobin

Lipemia: < 10% or 14umol/L up to 600mg/dL intralipid

Protein: < 20% or 28umol/L between 3 and 12 g/dL protein

Other: Rarely, gammopathy, especially monoclonal IgM (Waldenström’s macroglobulinemia), may cause unreliable results

Reference Range (µmol/L):
Children: 30.0 – 75.0 / Adult male: 59.0 – 104.0 / Adult female: 45.0 – 84.0