What labs should be run after a needle stick injury?

Laboratory Testing After a Needlestick Injury in Healthcare Settings

After a needlestick injury in a healthcare setting, comprehensive laboratory testing should be performed for both the exposed healthcare worker and the source patient, focusing on HIV, Hepatitis B, and Hepatitis C status. 1

Immediate Management

• Immediately wash the needlestick site or cut with soap and water 1
• If splashes to mucous membranes occur, flush the involved area with water 1
• Report the incident to your supervisor and document the exposure details 1
• Seek immediate medical evaluation for proper assessment and management 1

Laboratory Testing for the Source Patient

• Test the source patient (if known) for:

  • HIV antibody (rapid testing is available) 1
  • Hepatitis B surface antigen (HBsAg) 1
  • Hepatitis C antibody (anti-HCV) 1

• The source patient's testing should be obtained as soon as possible to guide post-exposure management decisions 1

Laboratory Testing for the Exposed Healthcare Worker

Baseline Testing (at time of exposure):

• HIV antibody test 1
• Hepatitis B serology:
  • If vaccination status is known and adequate: No testing needed 1
  • If vaccination status is unknown or inadequate: Test for Hepatitis B surface antibody (anti-HBs) 1
• Hepatitis C antibody (anti-HCV) 1
• Alanine aminotransferase (ALT) if source is HCV-positive 1

Follow-up Testing:

• For HIV exposure:

  • HIV antibody testing at 6 weeks, 3 months, and 6 months post-exposure 1
  • If post-exposure prophylaxis (PEP) is used, monitor for drug toxicity with complete blood count and renal/hepatic function tests 1

• For HCV exposure:

  • Anti-HCV and ALT at 4-6 months post-exposure 1
  • Some guidelines recommend HCV RNA testing at 4-6 weeks if earlier diagnosis is desired 1

• For HBV exposure:

  • Testing depends on the exposed person's vaccination and response status 1
  • If non-immune, test for HBsAg and anti-HBs at 6 months 1

Special Considerations

• The risk of HIV seroconversion after a percutaneous exposure to HIV-infected blood is approximately 0.36% (3.6 per 1,000 exposures) 2
• The risk of HBV transmission without prophylaxis may exceed 30% after exposure to HBeAg-positive blood 1
• Document all test results and maintain confidentiality of both the source patient and exposed worker 1
• Laboratory testing should be accompanied by appropriate counseling regarding risk of transmission, precautions to prevent secondary transmission, and signs/symptoms of viral infection 1

Common Pitfalls to Avoid

• Delaying or omitting source patient testing - this should be done immediately when possible 1
• Failing to document baseline serological status of the exposed worker 1
• Neglecting to consider the exposed worker's hepatitis B vaccination status when planning follow-up 1
• Overlooking the need for follow-up testing even when post-exposure prophylaxis is administered 1
• Not testing for all three major bloodborne pathogens (HIV, HBV, HCV) 1

By following these comprehensive testing protocols, healthcare facilities can properly assess risk, provide appropriate post-exposure prophylaxis when indicated, and monitor for potential infections following needlestick injuries.