Test Code CREAT Creatinine, Plasma or Serum with eGFR.
Performing Laboratory
MaineGeneral Medical Center
Specimen Requirements
Submit only 1 of the following specimens:
Preferred: Plasma
Draw blood in a green-top (lithium heparin) tube. For pediatric specimens, draw blood in a green-top (lithium heparin) MICROTAINER(S)®. Label the specimen with the patient's name (first and last), date of birth, date and time of draw, the phlebotomist's initials and as plasma. Spin down and send 1 mL of lithium heparin plasma refrigerated.
Alternate:
Serum
Draw blood in a gold-top (serum separater) gel tube. Label the specimen with the patient's name (first and last), date of birth, date and time of collection, the phlebotomist's initials and as serum. Spin down and send 1 mL of serum refrigerated.
Specimen stability:
24 hours at room temperature when spun
7 days refrigerated at 2-8°C
3 months frozen at ≥ -20°C
Minimum volume:
1 mL
Calculation
Estimated Glomerular Filtration Rate (eGFR) is calculated using the 4-variable MDRD equation for patients 18 years of age and older. The calculation incorporates serum creatinine, age, sex, and race (Black vs. non-Black).
For patients identified as Black, a race-specific adjustment factor is applied. If race is not specified, a non-Black coefficient is used.
eGFR values greater than 90 mL/min/1.73 m² are reported as >90.
Reference Values
Adult: 0.60-1.30 mg/dL
Critical value (automatic call-back): >5 mg/dL (excluding dialysis)
Day(s) Test Performed
Monday - Sunday
Methodology
Colorimetric (Jaffee) IDMS traceable
Test Classification and CPT Coding
82565