With the increasing prevalence of the acquired immunodeficiency syndrome (AIDS) cytology laboratories are processing increasing numbers of specimens from these patients. This has put a great stress on laboratories not only because of the requests for handling such specimens in an expedited (stat) manner but also because of the concerns about transmitting human immunodeficiency virus (HIV) to laboratory personnel.' The aim of this article is to provide some guidelines for cytology laboratories in order to minimize the risk of handling infectious specimens.
Approximately 5% of AIDS cases have occurred in health care workers (HCWs), corresponding to the same proportion as the labor force employed in Health Services in this country.2 The risk groups amongst the general population and HCWs are also similar except that there is a slight, and possibly statistically significant, difference between the "undetermined" risk category; i.e. about 3% for the general population and about 5% for H C W S . ~
There have been several long-term, prospective studies in the United States and abroad assessing the occupational risk of HIV transmission in HCWs. 3-17 One recent study from the National Institutes of Health (NIH) included 1,344 HCWs amongst whom there were 179 percutaneous and 346 mucous membrane HIV-1 exposures during a 6-year period. l7 In addition 559 of these HCWs reported more than 12,700 cutaneous exposures to blood, of which about 20% were from HIV-1-infected patients. One occupational transmission occurred in a HCW from parenteral exposure to blood; no transmission occurred after either mucous membrane or cutaneous exposures to infected blood.