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Test Code LACS1 Lactate, Plasma


Ordering Guidance


This test does not measure D-lactate, an uncommon, often undiagnosed cause of lactic acidosis. If D-lactate testing is needed, order DLAC / D-Lactate, Plasma.



Necessary Information


Patient's age and sex are required.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Gray top (potassium oxalate/sodium fluoride)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.625 mL Plasma

Collection Instructions:

1. Draw at least 1 mL whole blood in a 2-mL collection tube or at least 2 mL whole blood in a 4-mL collection tube.

2. Centrifuge and aliquot plasma into a plastic vial.


Secondary ID

601685

Useful For

Diagnosing and monitoring patients with lactic acidosis

 

Screening high-risk patients for sepsis or septic shock

Method Name

Enzymatic Colorimetric

Reporting Name

Lactate, P

Specimen Type

Plasma NaFl-KOx

Specimen Minimum Volume

Plasma: 0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma NaFl-KOx Refrigerated (preferred) 14 days
  Ambient  8 hours

Reject Due To

Gross hemolysis Reject

Clinical Information

Lactate is the end product of anaerobic carbohydrate metabolism and increases with prolonged exercise. Major sites of production are skeletal muscle, brain, and erythrocytes. Lactate is metabolized by the liver. The concentration of lactate depends on the rate of production and the rate of liver clearance. The liver can adequately clear lactate until the concentration reaches approximately 2.0 mmol/L. When this level is exceeded, lactate begins to accumulate rapidly. For example, while resting lactate levels are usually below 1 mmol/L, during strenuous exercise, levels can rise above 20 mmol/L within a few seconds.

 

Lactic acidosis signals the deterioration of the cellular oxidative process and is associated with hyperpnea, weakness, fatigue, stupor, and finally coma. These conditions may be irreversible, even after treatment is administered. Lactate acidosis may be associated with hypoxic conditions (eg, shock, hypovolemia, heart failure, pulmonary insufficiency), metabolic disorders (eg, diabetic ketoacidosis, malignancies), and toxin exposures (eg, ethanol, methanol, salicylates).

Reference Values

0-2 months: ≤3.3 mmol/L

3-24 months: ≤3.1 mmol/L

25 months-17 years: ≤2.2 mmol/L

> or  18 years: 0.5-2.0 mmol/L*

 

*Further information regarding the adult clinical action limit is available:

Townsend SR, Phillips GS, Duseja R, et al. Effects of compliance with the early management bundle (SEP-1) on mortality changes among medicare beneficiaries with sepsis: A propensity score matched cohort study. Chest. 2022;161(2):392-406. doi:10.1016/j.chest.2021.07.2167

Interpretation

While no definitive concentration of lactate has been established for the diagnosis of lactic acidosis, lactate concentrations exceeding 5 mmol/L and pH below 7.25 are generally considered indicative of significant lactic acidosis.

 

Elevated lactate (above laboratory reference interval or above 2.0 mmol/L in the absence of hypovolemia) in the context of sepsis evaluation in the hospital may warrant additional investigation to determine if sepsis or septic shock is present or developing.

 

Adult clinical action limit: Concentration greater than 2.0 mmol/L will flag as abnormal.(1)

Method Description

Lactate concentration is determined using an enzymatic colorimetric method. L-lactate is oxidized to pyruvate by the specific enzyme lactate oxidase. Peroxidase generates a colored dye using the hydrogen peroxide generated in the first reaction. The intensity of the color formed is directly proportional to the L-lactate concentration. Concentration is determined by measuring the increase in absorbance.(Package insert: Lactate. Roche Gen.2 Reagent; V15, 08/2024)

Day(s) Performed

Monday through Sunday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

83605

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LACS1 Lactate, P 2524-7

 

Result ID Test Result Name Result LOINC Value
LACS1 Lactate, P 2524-7