From the Guidelines
For a needle stick injury, baseline blood tests should include HIV, hepatitis B, and hepatitis C serologies for both the source patient (if known) and the injured healthcare worker, as recommended by the most recent guidelines 1. These tests establish the initial infection status and guide post-exposure prophylaxis decisions. Specifically, obtain:
- HIV antibody/antigen testing
- Hepatitis B surface antigen (HBsAg)
- Hepatitis B surface antibody (anti-HBs)
- Hepatitis B core antibody (anti-HBc)
- Hepatitis C antibody Additionally, liver function tests and complete blood count may be ordered to establish baseline values before potential prophylactic medications. Follow-up testing should occur at 6 weeks, 3 months, and 6 months post-exposure to detect potential seroconversion, as suggested by previous guidelines 1. These tests are crucial because bloodborne pathogens can transmit through percutaneous injuries, with transmission risk varying by pathogen (approximately 0.3% for HIV, 6-30% for hepatitis B, and 1.8% for hepatitis C per exposure) 1. Prompt testing enables appropriate prophylaxis decisions and early intervention if transmission occurs. It is also essential to provide psychological counseling to the exposed healthcare worker, as the psychologic impact of needlesticks or exposure to blood or body fluid should not be underestimated 1.
Some key points to consider:
- The source patient's serologic status should be determined if possible, to guide post-exposure prophylaxis decisions 1
- The injured healthcare worker's immunity to hepatitis B should be determined, and hepatitis B prophylaxis should be administered if necessary 1
- HIV post-exposure prophylaxis should be considered, and antimicrobial prophylaxis should be initiated as soon as possible but within 24 hours of exposure 1
- Follow-up care should include monitoring for adverse effects, serologic testing, and psychological counseling 1
From the Research
Blood Tests for Needle Stick Injury
The following blood tests are recommended after a needle stick injury:
- Hepatitis B surface antigen (HBsAg) test to detect hepatitis B virus 2
- Hepatitis C virus (HCV) antibody test to detect hepatitis C virus 2
- Human immunodeficiency virus (HIV) antibody test to detect HIV-1 and HIV-2 2
- Hepatitis B core antibody (anti-HBc) test to detect past exposure to hepatitis B virus 3
Testing for HIV, HCV, and HBV
Multiplex immunochromatographic rapid tests can simultaneously detect HIV-1, HIV-2, HCV, and HBsAg in serum, plasma, or whole blood samples 4. Automated chemiluminescent immunoassays (CLIAs) can also be used to detect HBV, HCV, and HIV in blood donor screening 5, 6.
Interpretation of Test Results
The results of these tests can help determine the risk of transmission of bloodborne pathogens and guide post-exposure prophylaxis (PEP) 2. The presence of HBsAg, HCV antibodies, or HIV antibodies in the source person's blood can indicate a high-risk injury, and PEP may be recommended accordingly 2.