Figure 2From: Lead exposure study among workers in lead acid battery repair units of transport service enterprises, Addis Ababa, Ethiopia: a cross-sectional study Distribution of subjects by group using urinary ALA levels. urinary ALA levels determined as described in the legend of Fig. 1 were used to classify subjects into different groups using ranges given by the manufacturer of the kit i.e. normal (<6 μg/ml), acceptable (6–20 μg/ml), high (20–40 μg/ml) and dangerous (>40 μg/ml).Back to article page