Investigation of hematuria at a printing company.

An investigation was undertaken at a printing company into an apparently high prevalence of trace dipstick hematuria discovered during routine medical examinations. In both the printing employees (n = 225) and a control group (n = 118) from other industries, the prevalence of hematuria exceeded that described in most previous reports (31% and 25%, respectively, using the criterion of > 12 glomerular red cells or > 2 nonglomerular red cells/microliter of urine). No focus of abnormality was identified within the printing plant and no association was identified between reported exposure to potentially toxic substances and the degree of hematuria. An occupational hygiene inspection and medical follow-up of selected workers did not reveal any significant abnormalities. The limitations of available information concerning "normal" urinalysis results suggests that hematuria may not be a useful test for the screening of occupational groups at risk of bladder cancer.