Comments on 'DNA-protein crosslinks, a biomarker of exposure to formaldehyde--in vitro and in vivo studies' by Shaham et al.

Shaham et al. (1) reported that the white blood cells (WBC*) of 12 anatomists and pathologists exposed to formaldehyde (FA) in a laboratory had significantly higher average levels of DNA—protein cross-links (DPC) than those of eight subjects 'who had never been exposed to FA'. Means and coefficients of variation (CV) (%SD) for DPC/total DNA were 0.288 (19%) for the exposed group and 0.227 (30%) for the unexposed group. Ranges of DPC/total DNA were 0.215-0.389 for exposed workers and 0.16-0.329 for the unexposed subjects. The range of exposure concentrations ('personal samples') was 2.8-3.1 p.p.m. There are several reasons to question whether the apparent difference in DPC represents a true difference and is due to FA.