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Epic Test Code LAB66 Creatinine: Serum (CRTN)

Important Note

Renal Function for Intravenous Contrast Media Injection Policy 

Performing Location(s)

BMC,CRH,LFH,HRK,OCH,FTT,FOX,FCC

Specimen Type

Serum or Plasma

Preferred Container

Gold or Red top tube

Alternate Container

Green top tube

Blood Tube Draw Volume

Min 50% draw volume  

Minimum Volume to Submit for Testing

0.5 mL Serum or Plasma

  • Multiple test can be performed from this volume. For question please contact the lab at 547-3975.  

Transportation Needs

 Deliver specimen to laboratory within 1 hour of collection if unspun. If not possible see "storage Requirements". 

Storage Requirements

Sample tubes should be centrifuged within 2 hours of collection 

Gold tops are stable in original tubes for 7 days DO NOT ALIQUOT

Aliquot Red tops

See Causes of Rejection for temperature requirements.

Causes for Rejection

Mislabeled or unlabeled specimen

Less than 50% draw for Vacutainer tubes
> 7 days refrigerated
> 48 hours room temperature
> 6 months Frozen
Hemolysis > 500 mg/dL HgB
Lipemia > 700 mg/dL Trig
Bilirubin > 20 mg/dL Bili

Limitations

Specific clinical settings in which eGFR is not appropriate for use and GFR should be measured directly include:

populations in which the MDRD equation is not validated (eg, Asian people)

severe malnutrition or obesity

extremes of body size and age <18 or >70 y.o.)

exceptional dietary intake (eg, vegetarian diet or creatine supplements)

disease of skeletal muscle, paraplegia, etc

rapidly changing kidney function.

 

The eGFR is not an accurate estimate of renal function in hospitalized patients due to the acute clinical status. Use caution in interpreting results in in-patients.

 

N-Acetylcystein (N-AC) interference with this method leading to falsely depresses values. Collecting blood work prior to drug administration and waiting ≥12 hrs for repeat testing is recommended.

Reference Values

Population

Units

Reference Range

Female

mg/dL

0.6-1.2

Male

mg/dL

0.7-1.3

 

Glomerular Filtration Rate (GFR) notes

The clinical laboratory automatically calculates glomerular filtration rate (GFR) on all adult out-patients with a creatinine. The GFR is usually accepted as the best overall index of kidney function in health and disease. The formula used will be that derived from the IDMS traceable Modification of Diet in Renal Disease (MDRD) study and recommended by the National Kidney Disease Education Program of the National Institute of Diabetes and Diseases of the Kidney, National Kidney Foundation and American Society of Nephrology. This equation is expected to provide a more accurate estimate of GFR than Creatinine Clearance. It uses serum creatinine in combination with patient age, sex and race to estimate GFR. The calculation (shown below) will be included on all adult out-patient’s with a serum creatinine at no charge.

 

Choosing Wisely:
Use Serum creatinine with eGFR and urinary albumin-creatinine ratio. (Renal Panel, LAB19)

Why is CKD Assessment Important?
Those with chronic kidney disease (CKD) diagnosed by a primary care clinician are more likley to:

  • Avoid risky uses of nonsteroidal anti-inflammatory drugs
  • Use angiotensin-converting-enzyme inhibitors or angiotensin receptor blockers when indicated.
  • Recevie approprate nephrology care

Epidemilogic data have shown that impaired kidney function increases the risk of systemic complications (eg, cardiovascular disease, hypertension, progression to end-stage renal disease, and mortality).

CKD, independent of the cause, is based on 3 or more months of either kidney damage (albuminuria) or an estimated glomerular filtration rate <60 mL/min/1.73 m2.

 

Who should be tested for CKD?

Asymptomatic individuales who are at high risk for CKD should be tested at least annually: diabets, hypertension, family history of kidney disease, and cardiovascular disease.

 

References:

  • Vassalotti JA, Centor R, Turner BJ, Greer RC, Choi M, Sequist TD/ Practical Approach to Detection and Management of Chronic Kidney Disease for the Primary Care Clinician. The American Journal of Medicine 2016;129:153-62.e7.
  • Choosing Wisely Recommendation for Chronic Kidney Disease Testing. 2018. at bit.ly/2SFSz3u
  • Inker LA, Astor BC, Fox CH, ET al. KDOQI US commentary on the 2012 KDIGO clinical practice guidelines for the evaluation and management of CKD. AM J Kidney Dis. 2014;63:713-35

Reflex Testing

A glomerular filtration rate (see Additional Information) will be calculated and reported on all adult out-patients with a creatinine, at no charge.

BCR is calculated on Inpatient orders only when both BUN and CRTN are ordered.

Days of Analysis

All

Available STAT

Yes

Methodology

Beckman AU/Dx Series

CPT Code

82565

Last Updated

26-OCT-24 MS