Post-Exposure Laboratory Testing
Immediately after occupational exposure to bloodborne pathogens, obtain baseline testing on both the exposed healthcare worker and the source patient: test the source for HBsAg, anti-HCV, and HIV antibody (using rapid testing when available), and establish baseline serology for the exposed worker to document pre-exposure status. 1
Immediate Testing Protocol
Source Patient Testing
The source patient should be tested immediately for:
- HBsAg (Hepatitis B surface antigen)
- Anti-HCV (Hepatitis C antibody)
- HIV antibody (consider rapid testing for faster results)
Critical caveat: Do not waste time testing discarded needles or syringes for virus contamination—this is not recommended and delays appropriate management 1.
Exposed Healthcare Worker Baseline Testing
At the time of exposure, assess the exposed worker's:
- Hepatitis B immune status by reviewing vaccination history and documented vaccine response
- Baseline HIV antibody (to establish pre-exposure status)
- Baseline anti-HCV and ALT (alanine aminotransferase) 1
If the worker will be started on HIV post-exposure prophylaxis (PEP), also obtain baseline laboratory tests to monitor for drug toxicity, with repeat testing every 2 weeks during the PEP course 1.
Follow-Up Testing Schedule
For HIV Exposure
- Baseline, 6 weeks, 3 months, and 6 months post-exposure
- Test immediately if acute retroviral syndrome symptoms develop
- Continue testing for at least 6 months 1
For HCV Exposure
Standard approach:
- Baseline anti-HCV and ALT
- Repeat anti-HCV and ALT at 4-6 months post-exposure
- Confirm repeatedly reactive anti-HCV enzyme immunoassays with supplemental tests 1
For earlier diagnosis (if desired):
- Perform HCV RNA at 4-6 weeks post-exposure 1
- Monthly ALT monitoring for 4 months, with qualitative HCV-RNA testing when ALT elevation is detected 2
For HBV Exposure
- If hepatitis B vaccine is administered post-exposure, test for anti-HBs 1-2 months after the last vaccine dose
- Note: Anti-HBs response cannot be accurately assessed if HBIG was given within the previous 3-4 months 1
Key Clinical Pitfalls
Timing matters: The entire evaluation and testing process should be completed rapidly to allow PEP initiation within 72 hours for HIV exposures and within 24 hours for HBV exposures in unvaccinated individuals 3, 4.
Don't skip baseline testing: Even if you're confident the worker was previously uninfected, baseline documentation is medicolegally essential and clinically necessary to distinguish pre-existing infection from occupational transmission 2, 5.
Unknown source patients: When the source patient cannot be identified or tested, assess the epidemiologic risk of HBV, HCV, or HIV exposure based on the clinical circumstances and proceed with appropriate prophylaxis and follow-up testing 1.