Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Creatinine is a breakdown product of creatine phosphate in muscle, which is usually produced at a constant rate by the body (depending on muscle mass). It is primarily filtered by the glomeruli in the kidney, but a small amount may be secreted by the proximal tubules. Creatinine is not re-absorbed to any appreciable extent by the tubules.
The assay of creatinine is the most commonly used test to assess renal function. It can be used to determine the presence and severity of chronic kidney disease (CKD) as well as identify a potential acute kidney injury (AKI).
The CKD-EPI equation is used to calculate the eGFR.
Specimen container paediatric:
Serum (SST or plain tube)
Specimen container adult:
Serum (SST or plain tube)
Minimum volume paediatric:
0.5 mL blood
Minimum volume adult:
1 mL blood
Sample stability:
Unseparated sample: 2 daysSeparated sample:
7 days at 15 to 25°C,
7 days at 4 to 8°C,
3 months at -20°C
Interpretation:
CKD is usually indicated when the GFR is <60 mL/min/1.73m2 for three months or more regardless of cause.AKI refers to a sudden decline in renal function and can be defined in terms of the proportional rise in serum creatinine from the baseline measurement and ranked in order of severity:
– AKI stage 1: Increase in serum creatinine 1.5 to 1.9 times baseline OR ≥26 µmol/l in >48 hours
– AKI stage 2: Increase in serum creatinine 2 to 3 times baseline
– AKI stage 3: Increase in serum creatinine 2 to 3 times baseline OR >354 µmol/l
Reference ranges:
Reference Ranges umo/L
Age Male Female
0-1m 27-77 27-77
1m-1y 14-34 14-34
1y-3y 15-31 15-31
3y-5y 23-37 23-37
5y-7y 25-42 25-42
7y-9y 30-47 30-47
9y-11y 29-56 29-56
11y-13y 39-60 39-60
13y-15y 40-68 40-68
>15y 59-104 45-84
Factors affecting result:
Significant interference is seen from paracetamol (acetaminophen), paracetamol metabolite N-acetyl-p-benzoquinone imine (NAPQUI), N-acetylcysteine (NAC) and metamidazole (novaminsulfone, dipyrone). The interference is most significant when the blood sample is taken while a significant plasma concentration of any these compounds is still present.
Other info:
Lithium heparin plasma samples also acceptable.