Q & A

March 2004

Q. What is the recommended protocol for testing an employee for hepatitis after a needlestick or biohazardous exposure?

A. Health care organizations must provide protocols for prompt evaluation, treatment, and followup of employees exposed to bloodborne pathogens.

The Occupational Safety and Health Administration requires employers to immediately make available a confidential medical evaluation and followup to a health care worker reporting a needlestick or biohazard exposure (29 CFR 1910.1030). Upon reporting an exposure, the health care worker should be evaluated and counseled regarding the risk of prophylaxis for HIV, hepatitis B virus, and hepatitis C virus and the need for followup evaluation.

Efforts also should be made to identify the source patient and to evaluate that person clinically and epidemiologically for evidence of HIV, HBV, and HCV infection. The source patient should be informed of the incident and must consent to testing.

The laboratory safety manual should provide detailed instructions for general first aid, specific treatment, prophylaxis, and counseling. Following an exposure incident, OSHA requires employers to document, at a minimum, the route of exposure and the circumstances under which the exposure incident occurred. The employer should provide information about engineering safety devices in use, protective equipment and clothing worn at the time of the exposure incident, and the employee's training. The employer should also make recommendations regarding how to avoid further incidents.

Many institutions use a protocol derived from Centers for Disease Control and Prevention updated guidelines. This report consolidates all U.S. Public Health Service recommendations for managing health care personnel who have occupational exposure to blood and other body fluids that might contain HBV, HCV, or HIV.

HBV post-exposure management includes initiating the hepatitis B vaccine series with any susceptible, unvaccinated health care employee who sustains an occupational blood or body fluid exposure. Post-exposure prophylaxis with hepatitis B immunoglobulin or the hepatitis B vaccine series, or both, should be considered once the source's hepatitis B surface antigen status and the exposed employee's vaccination or vaccine-response status are known.

As part of HCV post-exposure policy, management needs to determine the HCV status of the source and the exposed person. For health care personnel exposed to an HCV-positive source, followup HCV testing should be performed to determine if infection develops. Treatment of HCV varies, but immunoglobulin and antiretroviral agents, such as interferon with or without ribavirin, are not recommended for post-exposure prophylaxis of hepatitis C.

If the source of potential HIV infection is confirmed or known to be positive, the CDC recommends that HIV post-exposure prophylaxis include a basic four-week regimen of a combination of two drugs-zidovudine and lamivudine (ZDV + 3TC); lamivudine and stavudine (3TC + d4T); or didanosine and stavudine (ddI + d4T)-for most HIV exposures. An expanded regimen can include the addition of a third drug for those HIV exposures that pose an increased risk of transmission.

In addition, the CDC report outlines several special circumstances in which a laboratory should consult with local experts or contact the National Clinicians' Post-Exposure Prophylaxis Hotline (888-448-4911). Examples of such circumstances include a delayed exposure report, unknown source person, pregnancy in the exposed person, resistance of the source virus to antiretroviral agents, or toxicity of the post-exposure prophylaxis regimen.

Occupational exposures should always be considered urgent medical concerns to ensure timely post-exposure management and administration of hepatitis B immunoglobulin, hepatitis B vaccine, or HIV post-exposure prophylaxis.

The full CDC report is available online at www.cdc.gov/mmwr/ PDF/rr/ rrrr5011.pdf.

Bibliography

Beltrami EM, Williams IT, Shapiro CN, et al. Risk and management of blood-borne infections in health care workers. Clin Microbiol Rev. 2000;13:385-407.

Centers for Disease Control and Prevention. Updated U.S. Public Health Service guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for post-exposure prophylaxis. MMWR. 2001; 50(RR-11): 1-38. Available at www.cdc.gov/ mmwr/ PDF/rr/rr5011. pdf. Accessed Feb. 23, 2004.

NCCLS. Protection of Laboratory Workers from Occupationally Acquired Infection; Approved Guideline-Second Edition. NCCLS document M29-A2. Wayne, Pa.: NCCLS; 2001.

Public Health Service guidelines for the management of healthcare worker exposures to HIV and recommendations for post-exposure prophylaxis. Centers for Disease Control and Prevention. MMWR Recomm Rep. 1998;47(RR-7):1-33.

Thomas A. Merrick, MD
Department of Pathology
Presbyterian-St. Luke's
Medical Center
Denver
Chair, CAP Safety Committee

Chair, CAP Diagnostic Immunology
Resource Committee

Q. I work as a consultant to physician office laboratories that use waived coagulation monitors. Some providers want International Normalized Ratio, or INR, values above the therapeutic range verified with the reference lab; some want INR values from the waived meter only; and some don’t trust the waived meter. What guidelines do you recommend for POLs using a waived coagulation analyzer?

A. Waived coagulation instruments generally are very capable of making accurate INR measurements. To ensure accuracy, it is important that the laboratory establish a good quality control program to verify that the instrument and reagents function properly.

No specific CAP guidelines address how to handle abnormal or suspicious INR values that are obtained on waived devices. The laboratory, however, ultimately is responsible for establishing a documented system for verifying highly unusual results for each lab test (CAP hematology checklist No. HEM.20300: Is there a documented system in operation to verify highly unusual results for each laboratory test or instrument?).

To set up a verification system for unusual results, the lab should first consider any specific recommendations made by the instrument manufacturer. If the manufacturer does not provide recommendations, the lab should establish its own criteria. A practical approach is to repeat the test on the same instrument whenever the INR result is out of the reportable range or exceeds a predetermined number of INR units that are different from the previous INR result (delta check). If the INR value differs from clinical expectations, it may be prudent to verify the result on a separate venipuncture sample using a plasma-based reference method. If INR values from waived devices are to be verified using a reference method, it is highly recommended that the test methods be calibrated against each other.¹

Reference

1. Fairweather RB, Ansell J, van den Besselaar AM, et al. College of American Pathologists Conference XXXI on Laboratory Monitoring of Anticoagulant Therapy. Laboratory monitoring of oral anticoagulant therapy. Arch Pathol Lab Med. 1998;122:768–781.

Mark T. Cunningham, MD
Department of Pathology
University of Kansas Medical Center
Kansas City
Member, CAP Coagulation
Resource Committee