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Delivery on ice no longer required for lactic acid, plasma collected in grey-top tubes

The Department of Pathology & Laboratory Medicine at UCI Health has validated new stability requirements for lactic acid, plasma (lactate) collected in grey-top tubes. Transport on ice is no longer required. New stability limits are listed below. All other requirements remain the same.

Effective date: Immediately

Specimen requirement and testing information:

Specimen: Collect 4.0 mL whole blood in a grey-top tube (sodium fluoride/potassium oxalate). Blood should be drawn from a stasis-free vein. Invert tube 8-10 times to properly mix. Improper or delayed mixing may affect results. Do not shake. Spin down and separate plasma from cells within 2 hours of sample collection.

Test methodology: Enzymatic

Test code: LACTAT

Uncentrifuged whole blood:
Ambient: 2 hours
Refrigerated: 2 hours
Frozen: Unacceptable

Plasma, after centrifugation and separated from cells:
Ambient: Unacceptable
Refrigerated: 2 weeks
Frozen: 1 month

Turnaround time (TAT):
STAT: 60 minutes after receipt
Routine: 2 - 4 hours after receipt
Set Up Days: Daily

Specimen required: 1.0 mL plasma
Minimum volume: 0.5 mL plasma

Rejection criteria:
Specimens that exceed stated stability, unlabeled/mislabeled/mismatched specimens, specimens submitted in leaking containers, grossly hemolyzed specimens

  1. Astles R, Williams CP, Sedor F. Clin Chem 1994; 40(7):1327-30
  2. Mikesh LM, Bruns DE. Clin Chem 2008; 54(5):930-2
A summary of all tests offered by our laboratory services can be found here:


Bridgit O. Crews, PhD, DABCC
Clinical Chemistry & Toxicology

Edwin S. Monuki, MD, PhD
Department of Pathology & Laboratory Medicine
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