STABILITY OF PLASMA LACTATE IN-VITRO IN THE PRESENCE OF ANTIGLYCOLYTIC AGENTS

The use of plasma lactate to assess metabolic or circulatory impairmen t requires definition of critical preanalytical and analytical paramet ers. Stability has been documented for only 15 min after acquisition w hen samples were collected with fluoride and transported on ice. We ex amined time elapsed before analysis, storage temperature, and the anti glycolytic agent used to define preanalytical conditions. Plasma lacta te was measured with a Kodak Ektachem 700XR analyzer, in controlled st udies on volunteers, storage on ice slowed but did not eliminate the p roduction of lactate; for samples collected with sodium fluoride (F) a nd potassium oxalate (OX), lactate increased by 0.2 mmol/L after 1 h, then changed little regardless of the storage temperature. For patient s' samples collected in F/OX, the mean increase was only 0.15 mmol/L a fter 24 h. Samples with leukocytosis (neutrophil counts 23 x 10(9)-52 x 10(9)/L) were alsb stable, with a mean increase of 0.3 mmol/L at 8 h . Use of the antiglycolytic agents F and OX (at 60 and 12 mmol/L, resp ectively) maintained apparently stable lactate concentrations at room temperature for up to 8 h without special handling.