Overview
Lactate quantifies circulating lactic acid anion reflecting glycolytic overflow and clearance.
Clinical Importance
Assess shock/hypoperfusion and metabolic acidosis workups
Monitor critically ill patients when protocolized
Specimen Requirements
- Specimen: plasma (or whole blood for some point-of-care methods)
- Tube: gray-top sodium fluoride / potassium oxalate (or fluoride-EDTA) when glycolysis inhibition is required
- Alternative: lithium heparin or serum may be accepted if separated promptly; follow local method
- Handling: mix gently; separate cells promptly unless using a validated glycolysis inhibitor tube
- Stability: glucose falls in unseparated whole blood without inhibitor; lactate rises with delayed processing/exercise/tourniquet
Analytical Method
Enzymatic lactate oxidase or dehydrogenase methods with photometric or amperometric detection on chemistry or blood-gas platforms.
Instruments Used
Automated analyzers
- Roche Cobas chemistry and immunoassay systems
- Abbott Alinity / Architect chemistry and immunoassay systems
- Siemens Healthineers Atellica / ADVIA chemistry and immunoassay systems
- Beckman Coulter AU / DxC chemistry systems
- Beckman Coulter Access / DxI immunoassay systems
- Mindray BS-series chemistry analyzers
- Ortho Clinical Diagnostics Vitros systems
- Thermo Fisher / Indiko and related chemistry platforms
- Randox clinical chemistry systems
Manual methods
- Manual spectrophotometric/immunoassay methods in selected reference or backup settings
Reference Values
Typical adult SI examples below follow widely published international clinical chemistry practice (e.g., Tietz; Henry's). Always interpret against the method- and demographics-specific interval printed on the patient report (CLSI EP28-A3c). Neonatal, pediatric, pregnancy, and assay-generation intervals differ.
Typical published adult venous plasma lactate is often about 0.5–2.0 mmol/L; arterial values and method intervals differ.
Interpretation
Critical and significant-risk limits are institution-defined (CLSI GP47). Confirm the local call list. Textbook examples are not universal thresholds.
Critical values
- Markedly elevated lactate may be critical per ICU policy; verify locally
Common Causes of Increased Results
- Hyperlactatemia; correlate with perfusion, medications (e.g., metformin context), and liver clearance
Common Causes of Decreased Results
- Low values are seldom clinically actionable
Clinical Significance
- Sepsis/shock pathways
- Metabolic acidosis differential laboratory support
Factors Affecting Results
Pre-analytical
- Delayed separation, fist clenching, prolonged tourniquet, and delayed ice handling falsely raise lactate
- Hemolysis and strenuous exercise
Analytical
- Calibration/QC failure; reagent lot shifts
- Carryover or substrate depletion on high-throughput analyzers
- Assay-specific interference (heterophile antibodies for immunoassays)
Post-analytical
- Ignoring draw technique when interpreting mild elevations
Advantages and Limitations
Advantages
- Rapid marker of hypoperfusion when sampled correctly
Limitations
- Extremely preanalytical-sensitive
- Nonspecific causes of elevation
Clinical Pearls
A ‘high lactate’ from a difficult, delayed venous draw is often artifact until proven otherwise.
References
Authoritative textbooks, guidelines, and reviews supporting this laboratory test reference. Verify reference intervals, critical limits, and method details against institutional protocols and current guideline editions.
Textbooks
- Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 8th ed. Elsevier; 2022.
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2021.
- Bishop ML, Fody EP, Schoeff LE. Clinical Chemistry: Principles, Techniques, and Correlations. 9th ed. Jones & Bartlett; 2022.
CLSI and Professional Guidelines
- International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Recommendations and reference measurement systems for clinical chemistry measurands (verify current IFCC documents for the analyte).
- Clinical and Laboratory Standards Institute. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Standard. CLSI document EP28-A3c. CLSI; 2010.
- Clinical and Laboratory Standards Institute. Collection of Diagnostic Venous Blood Specimens. CLSI standard GP41. CLSI.
- American Diabetes Association. Standards of Care in Diabetes. Diabetes Care (annual update).
- Kidney Disease: Improving Global Outcomes (KDIGO). Clinical Practice Guideline for Evaluation and Management of Chronic Kidney Disease.
- American Association for the Study of Liver Diseases (AASLD). Practice guidance related to evaluation of abnormal liver chemistries / liver disease laboratory evaluation (verify current AASLD publication and institutional adoption).
Frequently Asked Questions
Common questions about using this Lactate laboratory test Medical Laboratory Library reference in Medical Laboratory Science education.
What is the Lactate laboratory test reference used for?
This Medical Laboratory Library page summarizes the clinical importance of Lactate. Review the Clinical Importance section for why the test is ordered in laboratory medicine practice.
Where can I find Lactate specimen requirements?
See the Specimen Requirements section on this page for specimen information related to Lactate. Confirm collection details against your laboratory protocol.
Where are Lactate reference values listed?
See the Reference Values section on this Laboratory Library page. Reference ranges can vary by method and population, so verify intervals with your laboratory.
How do I interpret Lactate results?
Use the Interpretation section for laboratory interpretation framing, including increased and decreased result patterns when provided. Do not treat educational text as a patient-specific diagnosis.
What analytical method is used for Lactate?
See the Analytical Method section for principle and method notes. Method details may differ by instrument and institutional SOP.
Are related laboratory tests linked from Lactate?
Yes. The Related Laboratory Tests section lists connected references for continued lookup in the Medical Laboratory Library.
How can I continue learning after reading Lactate?
Use Continue learning links on this page for related Academy lessons, medical laboratory quizzes, or laboratory case studies when available for this Clinical Chemistry topic.
What are the clinical pearls for Lactate?
See the Clinical Pearls section for concise laboratory practice notes associated with Lactate. Apply pearls alongside institutional protocols.
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