Should workers who might be exposed to H. capsulatum have pre-exposure skin or blood tests?
If a histoplasmin test was available again, workers at risk of exposure to H. capsulatum might learn useful information from skin testing. The results of skin testing would inform each worker of his or her status regarding either susceptibility to infection by H. capsulatum (a negative skin test) or partial protection against ill effects if reinfected (a positive skin test). However, a false-negative skin test result can be reported early in an infection or with persons with weakened immune systems. (6,8,14,26,34) A false-positive skin test can result from cross-reactions with antigens of certain other pathogenic fungi. (8,37) One drawback to routine pre-exposure skin testing is that a person with a positive skin test might incorrectly assume a false sense of security that he or she is completely protected against ill effects if reinfected. The work practices and personal protective equipment described in this booklet are expected to protect both skin-test positive and skin-test negati
