Interpretation

Arsenic:

Abnormal blood arsenic concentrations (>12 ng/mL) indicate significant exposure.

Absorbed arsenic is rapidly distributed into tissue storage sites with a blood half-life of less than 6 hours. Unless a blood specimen is drawn within 2 days of exposure, arsenic is not likely to be detected in a blood specimen.

Lead:

For pediatric patients, there may be an association with blood lead values of 5.0 to 9.9 mcg/dL and adverse health effects. The current reference level at which the Centers of Disease Control and Prevention recommends public health actions be initiated is 3.5 mcg/dL in patients 0 to 5 years old and 5 mcg/dL for patients 6 years and older. The most recent National Health and Nutrition Examination Survey (NHANES) data shows that 97.5 percentile for blood lead levels in US adults age 16 years and older is 3.46 mcg/dL. In concurrence with the reference value concept that there is no safe level of lead in blood, the Council of State and Territorial Epidemiologists Occupational Health Subcommittee approved lowering the blood lead threshold from 5 to 3.5 mcg/dL for adults. Follow-up testing after 3 to 6 months may be warranted.

Chelation therapy is indicated when whole blood lead concentration is greater than 25.0 mcg/dL in children or greater than 45.0 mcg/dL in adults.

The Occupational Safety and Health Administration has published the following standards for employees working in industry:

-Employees with a single whole blood lead result greater than 60.0 mcg/dL must be removed from workplace exposure.

-Employees with whole blood lead levels greater than 50.0 mcg/dL averaged over 3 blood samplings must be removed from workplace exposure.

-An employee may not return to work in a lead exposure environment until their whole blood lead level is less than 40 mcg/dL.

New York State has mandated inclusion of the following statement in reports for children under the age of 6 years with blood lead in the range of 5.0 to 9.9 mcg/dL: "Blood lead levels in the range of 5.0-9.9 mcg/dL have been associated with adverse health effects in children aged 6 years and younger."

Cadmium:

Normal blood cadmium concentration is less than 5.0 ng/mL, with most results in the range of 0.5 to 2.0 ng/mL.

Acute toxicity will be observed when the blood level exceeds 50 ng/mL.

Mercury:

The quantity of mercury (Hg) found in blood and urine correlates with degree of toxicity. Hair analysis can be used to document the time of peak exposure if the event was in the past.

Normal whole blood mercury concentration is usually less than 10 ng/mL.

Individuals who have mild exposure during work, such as dentists, may routinely have whole blood mercury levels up to 15 ng/mL.

Significant exposure is indicated when the whole blood mercury concentration is greater than 50 ng/mL if exposure is due to alkyl Hg, or greater than 200 ng/mL if exposure is due to Hg(2+).