Increased urinary output of ALA and coproporphyrine is a significant index of metabolic damage: thus, determination of the two urinary metabolites is a test of poisoning. Determination of lead in urine reveals the type of poisoning but does not necessarily express its extent. Sufficiently precise limits must be set to 'normality', that is, to the state corresponding to exposure to lead due only to the general background. For practical reasons, determinations are carried out, particularly during work time on samples of extempore urines: so in order to set limits to 'normality', one must adopt correction criteria of variable urinary density and of the subject's particular endogenous metabolism. This correction is brought about by reckoning the direct ratio between concentration of substances (under examination) and creatine concentration (ALA mg%/Creatinine mg%; Coproporphyrine μg%/Creatinine mg%; Lead μg%/Creatinine mg%). In wider diuresis variations (proper to work conditions), urinary elaboration (filteringreabsorption) may possibly have a different effect on output of single substances; in which case it may be useful to get output ratios (between substances being examined and creatinine) obtained from individual relations where the output (UxV) is related to U/osm. The data observed are expressed in simple concentrations, in direct ratio to creatinine, and also in calculated ratio. For the general population examined, (550 subjects not professionally exposed, and homogeneously divided between urban and rural districts of the Emilia Romagna Region), results for maximum dispersion limits (m + 2 sigma) are reported. For subjects professionally exposed, data expressed in terms of output ratios show an important correlation between ALA and Coproporphyrine, that decidedly appears with values immediately above the limits of the general population. This behaviour allows an interpretation of the limit of 'normality'. For practical purpose, the finding in the single subject of values beyond the maximum limit must be regarded as an expression of metabolic damage, so much as to exclude possible valuations in terms of 'acceptability'.
|Translated title of the contribution||Meaning and limits of urinary biological index in lead exposure|
|Number of pages||6|
|Journal||Medicina del Lavoro|
|Publication status||Published - 1975|
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health