Lactic Acid



To assess for lactic acid acidosis related to poor tissue or organ perfusion and failure.

Patient Preparation
There are no activity or medication restrictions unless by medical direction. Instruct the patient to fast and to restrict fluids overnight. Instruct the patient not to ingest alcohol for 12 hr before the test. Protocols may vary among facilities.

Normal Findings
Method: Spectrophotometry/enzymatic analysis.

Conventional UnitsSI Units (Conventional Units × 0.111)
0–90 d3–32 mg/dL0.3–3.6 mmol/L
3–24 mo3–30 mg/dL0.3–3.3 mmol/L
2 yr–adult3–23 mg/dL0.3–2.6 mmol/L

Critical Findings and Potential Interventions
Lactic acidemia is defined as a sustained, mild to moderate increase above normal in lactic acid levels without metabolic acidosis. Lactic acidemia can occur with balanced acid-base concentrations, sufficient tissue perfusion, and adequate tissue oxygenation. Lactic acidosis is defined by a sustained increase, two-times or greater than normal, in lactic acid levels and is associated with metabolic acidosis. Lactic acidosis is associated with significant disruptions in metabolic processes and tissue hypoperfusion.Adults

  • Greater than 31 mg/dL (SI: Greater than 3.4 mmol/L).


  • Greater than 37 mg/dL (SI: Greater than 4.1 mmol/L).

Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.

Consideration may be given to verification of critical findings before action is taken. Policies vary among facilities and may include requesting immediate recollection and retesting by the laboratory or retesting using a rapid point-of-care testing instrument at the bedside, if available.

Observe the patient for signs and symptoms of elevated levels of lactate, such as Kussmaul breathing and increased pulse rate. In general, there is an inverse relationship between critically elevated lactate levels and survival.

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