Creatinine, Plasma

Overview
Department	Biochemistry
Test Code	PCRN
Synonyms	CRN, plasma
Base Lab Availability	Monday - Sunday, testing routinely available out of hours
Hawera Lab Availability	Monday - Friday, 8am to 4 30pm
Turnaround Time	1 hour urgent - 2 hours routine
Stability – Add test	24 hours
Specimen Requirements
Specimen	Serum Plasma
Preferred	6 mL Plain Red-Top
Acceptable	4 mL Li-Heparin Green-Top
Specimen Transportation
Pediatric Requirements	600 µL   Li-Heparin Microtainer
Aliquot Requirements
Sample	Plasma Serum
Preferred Volume	100 µL
Minimum Volume
Aliquot Transportation
Clinical Information
Reference Intervals	Creatinine µmol/L 0 - < 1 week < 90 1 week - < 4 weeks < 50 4 weeks - < 2 years < 40 2 years - < 6 years < 50 6 years - < 12 years < 65 12 years to < 15 years < 80 Male >15yr + Adult 50 -  110   Female >15 yr + Adult 45 - 90 CKD-EPI calculation for eGFR Reference range: 80 - 120 mL/min/1.73 m2 Female Crn ≤62 eGFR (ml/min) = 144 x [Crn(µmol/L)/0.7]-0.329 x [0.993] Age. Crn >62 eGFR (ml/min) = 144 x [Crn(µmol/L)/0.7]-1.209 x [0.993] Age. Male  Crn ≤80 eGFR (ml/min) = 141 x [Crn(µmol/L)/0.9]-0.411 x [0.993] Age. Crn >80 eGFR (ml/min) = 141 x [Crn(µmol/L)/0.9]- 1.209 x [0.993] Age. Children < 16 years- no calculation done Interpretation Estimated GFR is only reliable under steady state conditions (stable Creatinine >4 days). Caution should be used in interpretation in non-Caucasians, extremes of body weight, pregnancy, oedematous subjects, low Creatinine (<0.06mmol/L) and other complex cases. GFR declines by 1 ml/min/year over 40 years.
Test Method	Methodology: Enzymatic Creatinine assay using Abbott reagent on the Alinity c series (Base) and Architect c8000 (Hawera) analyser. eGFR routinely reported on all valid samples (patients < 16 years excluded).  Calculated using the plasma creatinine and CKD-EPI calculation.
Advanced Notice	Not required
Patient Preparation	Not required
Comments

Owner	Clair Crossley (Crossley1)
Last reviewed	14.01.2026
Next review	14.01.2027 (OK)