A Simple Enzymatic Method for the Measurement of Abnormal Levels of Formate in Plasma

Abstract

A simple and practical method designed to measure abnormal concentrations of plasma formate is described. The method uses formate dehydrogenase and a color reagent to produce a stable formazan color. The method requires no deproteinization and has a one-point standard calibration. The precision at 1.0 and 5.0 mmol/L formate is 2.9% and 1.7% within-day and 5.5% and 2.3% between-day. Recovery averages 100% for formate concentrations of 2.0 to 10.0 mmol/L. The proposed method is inexpensive, robust, and suitable for routine use and shares the color reagent used for the assay of plasma lactate and 3-hydroxybutyrate, both important analytes in metabolic acidosis.

Microbial surface displaying formate dehydrogenase and its application in optical detection of formate

“…And the results obtained through enzymatic method correlated well with those values measured by above methods [9,10]. Nevertheless, the use of free enzyme could be limited by laborious operations and high cost for isolation and purification of intracellular expressed enzymes, as well as the poor stability of the enzyme.…”

Elevated formic acid concentrations in putrefied post-mortem blood and urine samples

“…In previous studies, the mean plasma FA concentration in living subjects has ranged from 0.001 to 0.009 g/l [8][9][10]. However, large individual variation in plasma FA concentrations of 69 pregnant women, ranging from 0.0005 to 0.044 g/l, has been reported [10].…”

“…Enzymatic methods have also been used to quantify FA in tissue samples [8,12]. Recently, we published a method for FA, ethylene glycol, glycolic acid and other polar hydroxylic compounds by HS in-tube extraction GC coupled to mass spectrometry (ITEX-GC-MS) [13].…”

Fatal intoxication with a decalcifying agent containing formic acid

“…As reported in the literature, formic acid concentrations in the blood of healthy humans range from 3.2-56 µg/ml [24,26,27,28,29,30]. Hence the formic acid content of the blood at the time of admission to hospital and of the post-mortem heart blood was much greater than normal biological levels.…”