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Test Code CREAT CreatiNINE

Clinical System Name



Serum creatinine is increased in acute or chronic renal failure, urinary tract obstruction, reduced renal blood flow, shock, dehydration, exercise, and rhabdomyolysis.  Causes of low serum creatinine concentration include debilitation, and decreased muscle mass. The creatinine clearance rate is unreliable if the urine flow is low.  Since urinary creatinine is excreted mainly by glomerular filtration, with only small amounts due to tubular secretion, serum creatinine and a 24-hour urine creatinine excretion can be used to estimate the glomerular filtration rate. 

Sample Requirements

Specimen: Whole Blood

Container(s): Gold SST, Dark Green/Sodium Heparin, Red, Gold Microtainer, Lt. Green/Li Heparin Microtainer

Preferred Vol: 1.0 mL

Minimum Vol: 0.5 mL

Note:  Method is affected by gross hemolysis and lipemia. Not affected by heparin.


Processing Instructions

Reject due to: Hemolysis, Age of specimen

Spin: Y

Aliquot: Y

Temp: 2-8oC

Storage location: Core 5 Chemistry Refrigerator


Off-site collection: Avoid hemolysis. Spin blood, refrigerate serum or plasma in plastic aliquot container.



Specimen Type Temperature Time
Serum or Plasma RT

5 D

Serum or Plasma 2-8oC

 30 D

Serum or Plasma -20oC or -70oC

365 D



STAT Performed TAT
Y 24/7 1 H


Performing Laboratory

Seattle Children's Laboratory    


Department:  Core Chemistry

Phone Number: 206-987-2617

Reference Range


 Age mG/dL
0 - 1 W 0.2 - 1.1
1 W- 2 M 0.1 - 0.6
2 M- 2 Y 0.1 - 0.4
2 Y- 10 Y 0.1 - 0.6
10 Y- 14 Y 0.2 - 0.9
> 14 Y 0.2 - 1.1



Method:  Two Point Rate by Vitros 4600

Analytical Volume:  0.02 mL + 0.03 mL dead space

CPT Codes