What blood tests are required after a needle stick injury?

Blood Tests Required After a Needle Stick Injury

Following a needle stick injury, immediate testing should include HBV (HBsAg and anti-HBs), HCV (antibody to HCV and ALT), and HIV antibody tests for both the exposed person and the source patient (when known). 1

Initial Testing Protocol

Source Patient Testing

When the source patient is known, obtain the following tests:

• Hepatitis B surface antigen (HBsAg)
• Hepatitis C antibody (anti-HCV)
• HIV antibody test

Exposed Person Testing

Baseline testing of the exposed healthcare worker should include:

• Hepatitis B surface antibody (anti-HBs) - to determine immunity status
• Hepatitis C antibody (anti-HCV)
• Alanine aminotransferase (ALT)
• HIV antibody test

Follow-up Testing

For HCV Exposure

• Test the exposed person for anti-HCV and ALT at baseline and again at 4-6 months post-exposure 1
• No post-exposure prophylaxis is currently recommended for HCV exposures

For HIV Exposure

• Follow-up HIV antibody testing at appropriate intervals if source patient is HIV-positive
• Testing should be performed in conjunction with post-exposure prophylaxis (PEP) if initiated

For HBV Exposure

• Follow-up testing depends on the exposed person's vaccination status and antibody response
• For those with adequate antibody levels (>100 IU), the risk of HBV transmission is virtually zero 1

Important Considerations

Timing of Testing

• Initial testing should be done as soon as possible after the exposure
• Studies show that approximately 86.5% of index patients undergo serological testing for HBV, HCV, and HIV 2

Documentation Requirements

• Document the circumstances of the injury
• Record test results of both source patient and exposed person
• Track follow-up testing compliance

Common Pitfalls to Avoid

1. Failure to report the injury: Studies show that up to 75% of NSIs in developing countries go unreported 3
2. Inadequate initial response: The most appropriate immediate actions include washing the wound with soap and water and encouraging bleeding 4
3. Neglecting follow-up testing: Only about 44.6% of injured personnel pursue follow-up measures after a needle stick injury 5
4. Incomplete source testing: Ensure all three major bloodborne pathogens (HBV, HCV, HIV) are tested in the source patient

Risk Assessment

• The risk of HIV seroconversion after a single needlestick involving HIV-infected blood is approximately 0.36% 1
• Without prophylaxis, the risk of HBV transmission may exceed 30% after exposure to HBeAg-positive blood 1
• One in five source patients may be infected with at least one bloodborne pathogen 2

Remember that complete reporting and testing are prerequisites for identifying risky procedures and ensuring optimal treatment of affected healthcare workers 2.