Wide variation in reference values for aluminum levels in children.

Background: Some parents are requesting aluminum testing in their children with developmental issues. Although aluminum can be measured in plasma, serum, or urine, there is scant scientific information about normal ranges. We sought to determine the basis for laboratory reference ranges and whether these ranges are applicable to children.

Methods: From texts, published lists, and Internet sources, we obtained the names of 10 clinical laboratories that perform aluminum testing. Contact was made by telephone or e-mail, or Internet sites were viewed to obtain information regarding the establishment of aluminum reference ranges and testing methods in biological samples. Seven laboratories provided supporting literature that was reviewed regarding details of the study populations.

Results: For laboratories using the atomic absorption spectrometry method, aluminum reference ranges varied from <5.41 μg/L to <20 μg/L (serum), <7.00 μg/L to 0 to 10 μg/L (plasma) and 5 to 30 μg/L (urine). For those using the inductively coupled plasma mass spectroscopy methodology, ranges varied from 0 to 6 μg/L to <42 μg/L (serum), 0 to 10 μg/L to 0 to 15 μg/L (plasma), and 0 to 7 μg/L to 5 to 30 μg/L (urine). None of the reference ranges are known to be derived from studies of healthy children, but relied instead on small studies of adult populations, adult dialysis patients, workers, or sick children on aluminum-containing parenteral therapy.

Conclusions: Aluminum reference ranges provided by laboratories are widely divergent, may not represent "normal" ranges of a healthy population, especially children, and thus it is difficult to interpret serum or urine aluminum ranges clinically. Further studies of aluminum in children are warranted and should be considered as part of the Centers for Disease Control and Prevention Biomonitoring Project.