[Usefulness of delta-aminolevulinic acid in blood as an indicator of lead exposure].

The concentration of delta-aminolevulinic acid in blood (ALA-B) was determined using high performance liquid chromatography (HPLC). To improve the chromatographic separation and the recovery rate of ALA determination in blood, acetate buffer was used in the reaction mixture of fluorescence derivatization. The detection limit of ALA-B was ca. 2 micrograms/l at signal to noise ratio of 5, and the analytical recovery was 102.0 +/- 4.10% (mean +/- SD), when 50 micrograms/l of ALA was added to 7 blood samples (ALA-B levels: 6.5-103.0 micrograms/l). ALA-B levels in control subjects (n = 19) were 5.3 +/- 1.4 micrograms/l (mean +/- SD) and those in 52 lead workers (blood lead levels (Pb-B): 2.4-86.2 micrograms/dl) were 15.4 +/- 12.2 micrograms/l (range: 3.1-137.3 micrograms/l). Standard curve of ALA was linear over a wide range, at least up to 400 micrograms/l. In the workers, the correlation coefficients of ALA-B vs. Pb-B and ALA-B vs. delta-aminolevulinic acid dehydratase activity (ALA-D) were higher than those of urinary concentration of ALA vs. Pb-B and that vs. ALA-D, especially in the moderate Pb-B level (less than 40 micrograms/dl, n = 35). Unless the urinary concentrations of ALA were not corrected, significant correlation could not be found between Pb-B and urinary ALA in the workers moderately exposed to lead, and the correlation coefficient between urinary ALA and ALA-D was -0.354, while the correlation coefficients of ALA-B vs. Pb-B and ALA-B vs. ALA-D were 0.739 and -0.746, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)