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Test Code CREA Creatinine with Glomerular Filtration Rate (GFR), Plasma or Serum

Methodology

Colorimetric, Jaffe Reaction

Performing Laboratory

Aspen Valley Hospital

Specimen Requirements

Submit only 1 of the following specimens:

 

Preferred:

Plasma

Container/Tube:  Light green-top (lithium heparin gel) tube(s)

Specimen:  2 mL (minimum volume:  1 mL) of lithium heparin plasma
Transport Temperature:  Ambient
Collection Instructions:  Spin down immediately and send entire tube to laboratory. If there is a delay in transport of >8 hours, send specimen refrigerated.

Note:  1. Indicate plasma on request form.
2. Label specimen appropriately (plasma).

 

Alternate:

Serum
Container/Tube:
  Gold-top serum gel tube(s) or Plain, red-top tube is also acceptable.

Specimen:  2 mL (minimum volume:  1 mL) of serum
Transport Temperature:  Ambient

Collection Instructions:  Allow specimen to clot for approximately 10 minutes and spin down. If drawing gold-top serum gel tube, send entire tube to laboratory. If red-top tube, remove serum and place in separate plastic vial. If there is a delay in transport of >8 hours, send specimen refrigerated.

Note:  1. Indicate serum on request form.
2. Label specimen appropriately (serum).

Reference Values

Creatinine:  0.6-1.3 mg/dL

GFR:  ≥60

INTERPRETATION

Normal GFR:  ≥60

Moderate reduction in GFR:  30-59

Severe reduction in GFR:  15-29

Kidney failure:  <15

 

Critical Value: ≥ 5.0 mg/dL

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

82565