Microbore glass capillary tubes, used for hematocrit determination, pose a serious and avoidable risk of blood-borne pathogen transmission to health care workers. The fragile blood-filled tubes sometimes break, especially when the health care worker pushes one end of the tube into sealing clay. The glass typically fractures near the worker's fingers where force is applied and can cause lacerations and introduce blood directly into the wound. One such injury transmitted human immunodeficiency virus to a physician who has since died of acquired immunodeficiency syndrome.1 Sometimes capillary tubes shatter during centrifugation, posing further risk of injury and blood exposure to staff when they remove glass shards and clean spilled blood. Nationally, the exact number of glass capillary tube injuries is not known. At the University of Virginia Hospital, Charlottesville, in 1992, before the elimination of glass capillary tubes, 2.6 injuries per 100000 tubes purchased were reported. According to industry estimates, approximately 108 million glass capillary tubes are sold annually in the United States (W. Kendrick, written communication, June 5, 1998). This rate extrapolates nationally to approximately 2800 capillary tube injuries per year in health care settings. We examined data from a 77-hospital surveillance database on percutaneous injuries to health care personnel.2 From 1993 through 1996, 38 injuries from glass capillary tubes were reported. Twenty injuries (53%) occurred in clinical laboratories, 6 (16%) in intensive or critical care units, 3 (8%) in outpatient clinics, and 9 (24%) in emergency departments, blood banks, dialysis units, procedure rooms, utility areas, or labor and delivery units. We also reviewed data from a hospital-based employee health surveillance system (National Surveillance System for Hospital Health Care Workers) now being developed by the Centers for Disease Control and Prevention. As of January 1998, the participating hospitals reported 1261 percutaneous injuries that resulted in workers becoming exposed to blood or body fluids, of which 5 (0.4%) were caused by capillary tubes. Three occurred in emergency departments, 1 in a pediatrics unit, and 1 in a clinical laboratory. All 5 tubes were visibly contaminated with blood prior to the exposure, and antiretroviral prophylactic therapy was initiated by 2 exposed health care workers. In 4 cases, the contaminated, broken tube perforated the worker's glove, and in 1 case perforated double gloves. We are aware of at least 3 safer alternatives on the market: plastic capillary tubes, Mylar-wrapped glass capillary tubes, and a hemoglobin reader that uses a flat plastic microcuvette to contain the blood sample. In 1993, the Food and Drug Administration cautioned against the continued use of glass capillary tubes,3 but increased awareness is needed. At present, it is unnecessary to expose health care workers to the risks of glass lacerations, blood exposure, and potential transmission of blood-borne pathogens that accompany the use of microbore glass capillary tubes. Using alternatives to plain glass capillary tubes for hematocrit testing should protect health care workers from this source of exposure to blood-borne pathogens. Preventing injuries remains the primary method to prevent occupational transmission of blood-borne pathogens.