Children with moderately elevated blood lead levels: a role for other diagnostic tests?

Abstract

In this study we examined potential limitations of relying excdusively on blood lead (BPb) levels to evaluate children with moderatdy elevated BPb levels (1.21-2.12 pmol/l, or 25-44 pg/dl).We tested the following hypotheses: 1) such children without elevated erythrocyte protoporphyrin (EP) levels (.0.62

Predicting the Outcome of the CaNa 2 EDTA Challenge Test in Children with Moderately Elevated Blood Lead Levels

“…Other studies have reported rates of positive challenge tests comparable to those in our study (15,17,18 …”

“…A low EP level is excellent at identifying such children; only 3% of challenge tests with an EP level < 0.62 pmol/L (< 35 pg/dL) were positive. This finding is comparable to the 4.8% reported by Markowitz et al (15). A decreasing blood lead level is a fair predictor of a negative challenge test; 86% of children whose blood lead level was decreasing (i.e., RATE < 0 pg/dL/day) had a negative challenge test.…”

“…Additionally, certain blood lead levels were also predictive of a negative challenge test; no challenge tests were positive at blood lead levels < 1.40 pmol/L (< 29 pg/dL). Previous studies report that iron deficiency is associated with a lowered likelihood of a positive challenge test (10,15). Our study found that iron saturation did not reliably distinguish the outcome of a challenge test; this is not surprising because iron status was previously noted to be weakly associated with the outcome of the challenge test (10) 4 weeks of the diagnosis.…”

“…This reflects the heterogeneity that exists within the population of lead-exposed children and highlights the limitations of the blood lead level in determining whom to chelate. Authors have raised this issue and argued that the challenge test is useful for identifying whom to treat when blood lead levels are moderately elevated (15,16). Our study supports this contention.…”

Primary Prevention of Childhood Lead Poisoning — The Only Solution

“…1 In affected children, whose blood lead levels were often greater than 100 µg per deciliter, chelating agents rapidly lowered blood lead levels by brisk diuresis and stopped the progression of lead poisoning to the point of frank encephalopathy. 8,9 This treatment saved lives but did not eliminate the neurologic consequences, which were permanent. Very rarely, if ever, does chelation therapy for such severe lead poisoning reverse or prevent the signs and symptoms of lead-induced neurotoxicity.…”