Test Code LAB11 Creatinine, Plasma or Serum

Additional Codes

Test Name in EPIC	EPIC Test Code	Mnemonic
CREATININE	LAB11	CREAT

Useful For/Utility

Calculation of creatinine clearance, a measure of renal function, when used in conjunction with serum creatinine
Normalization of urinary analytes by creatinine concentration to account for the variation in urinary concentrations between subjects

Methodology

Kinetic Alkaline Picrate

Clinical Information

Creatinine is formed from the metabolism of creatine and phosphocreatine, both of which are principally found in muscle. Thus, the amount of creatinine produced is, in large part, dependent upon the individual's muscle mass and tends not to fluctuate much from day-to-day.
Creatinine is not protein bound and is freely filtered by glomeruli. All of the filtered creatinine is excreted in the urine. Renal tubular secretion of creatinine also contributes to a small proportion of excreted creatinine. Although most excreted creatinine is derived from an individual's muscle, dietary protein intake, particularly of cooked meat, can contribute to urinary creatinine levels.
The renal clearance of creatinine provides an estimate of glomerular filtration rate. Since creatinine, for the most part, in the urine only comes from filtration, the concentration of creatinine reflects overall urinary concentration. Therefore, creatinine can be used to normalize other analytes in a random urine specimen.

Specimen Requirements

Submit only 1 of the following specimens:

Preferred:

Specimen Type: Plasma

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

Specimen Volume: 1 mL

Specimen Minimum Volume: 0.5 mL

Collection Instructions:

1. Separate plasma from cells within 2 hours of draw.

2. If plunger filters are used, immediate removal of plasma is indicated unless an air gap can be created between the device and specimen.

Additional Information:

1. Avoid repeated freeze/thaw cycles.
2. Label specimen appropriately (plasma).

Alternate:

Specimen Type: Serum

Container/Tube: Serum gel

Specimen Volume: 1 mL

Specimen Minimum Volume: 0.5 mL

Collection Instructions:

1. Separate serum from cells within 2 hours of draw.

2. If plunger filters are used, immediate removal of serum is indicated unless an air gap can be created between the device and specimen.

Additional Information:

1. Avoid repeated freeze/thaw cycles.
2. Label specimen appropriately (serum).

Specimen Transport Temperature

Refrigerate 5 days/Ambient 8 hours OK/Frozen OK

Day(s) Test Set Up

Monday through Sunday

Performing Laboratory

Chemistry -

St. Joseph's - Baxter Clinic Lab, St. Joseph's - Brainerd Clinic Lab, St. Joseph's Medical Center Lab

Ashland Clinic Lab, Deer River Hospital Lab, Ely Clinic Lab, Hayward Clinic Lab, Hibbing Clinic Lab, International Falls Clinic Lab, Moose Lake Hospital Lab, Northern Pines Lab, Sandstone Hospital Lab, SMDC Clinical Lab, Spooner Clinic Lab, St. Mary's Hospital - Superior Lab, Virginia Hospital Lab

Ada Hospital Lab, Fargo Hospital Lab, Fosston Hospital Lab, Holy Trinity Hospital Lab, Park Rapids Clinic Lab, South University Clinic Lab, St. Mary's - Detroit Lakes Hospital Lab

Test Classification and CPT Coding

82565

Reference Values

Males

0-14 days: 0.42-1.05 mg/dL

15 days-1 year: 0.31-0.53 mg/dL

1-3 years: 0.39-0.55 mg/dL

4-6 years: 0.44-0.65 mg/dL

7-11 years: 0.52-0.69 mg/dL

12-14 years: 0.57-0.8 mg/dL

15-16 years: 0.65-1.04 mg/dL

17-18 years: 0.69-1.1 mg/dL

Adult: 0.7-1.2 mg/dL

Females

0-14 days:0.42-1.05 mg/dL