What is the recommended course of action after being cut with a knife containing dried blood from an individual of unknown Human Immunodeficiency Virus (HIV) status?

Immediate Management of Knife Injury with Dried Blood Exposure

You should immediately wash the wound thoroughly with soap and water, seek urgent medical evaluation within 2 hours for HIV post-exposure prophylaxis (PEP) consideration, and obtain baseline and follow-up HIV testing. 1

Immediate First Aid (Within Minutes)

• Wash the wound immediately with soap and running water for at least 15 minutes to reduce viral load at the exposure site 2
• Do not squeeze or manipulate the wound, as this may increase tissue damage and potential viral penetration 1
• Allow the wound to bleed freely briefly if actively bleeding, then apply pressure for hemostasis 1

Risk Assessment Context

The actual transmission risk from this exposure is extremely low for several important reasons:

• Dried blood has significantly reduced HIV viability - HIV is fragile outside the body and loses infectivity rapidly when blood dries 1
• The baseline risk of HIV transmission from a percutaneous injury with fresh HIV-infected blood is only 0.3% (95% CI: 0.2%-0.5%) 1, 3
• The source person's age (early twenties) and unknown HIV status means the probability they are HIV-positive is relatively low in most populations 1
• Hepatitis B poses a much higher risk at approximately 30% transmission rate from HBeAg-positive blood, making HBV the primary concern 1

Urgent Medical Evaluation (Within 2 Hours)

Time is critical - PEP is most effective when started within 2 hours and should ideally be initiated within 72 hours maximum 1, 4:

• Present to an emergency department or occupational health service immediately 1
• Bring information about the exposure circumstances and any details about the source individual if available 1
• Do not delay seeking care even if the source person's HIV status is unknown 1

Post-Exposure Prophylaxis Decision

HIV PEP Considerations:

PEP may be offered but is not automatically indicated for dried blood exposure 1:

• The decision depends on: depth of injury, visible blood contamination on the knife, and estimated time since blood dried 1, 3
• If PEP is recommended, the standard regimen is zidovudine plus lamivudine for 4 weeks, with consideration of adding a protease inhibitor for higher-risk exposures 4
• Zidovudine prophylaxis reduces HIV transmission risk by approximately 80% when administered after exposure 4, 3

Hepatitis B Management:

This is the higher priority bloodborne pathogen concern 1:

• If you are unvaccinated or incompletely vaccinated for hepatitis B, you should receive hepatitis B immune globulin (HBIG) and initiate or complete the vaccine series 1
• If you are vaccinated with documented immunity, no additional HBV prophylaxis is needed 1

Hepatitis C Assessment:

• Baseline and follow-up testing for hepatitis C should be performed 1
• No post-exposure prophylaxis is available for HCV, but early detection allows for prompt treatment if transmission occurs 1

Testing Protocol

Baseline testing (day 0): 1

• HIV antibody test
• Hepatitis B surface antibody (if vaccination status unknown)
• Hepatitis C antibody
• Complete blood count and liver function tests if PEP is initiated

Follow-up testing schedule: 1

• HIV testing at 6 weeks, 3 months, and 6 months post-exposure
• Hepatitis C testing at 3-6 months
• Earlier testing if symptoms of acute retroviral syndrome develop (fever, rash, lymphadenopathy)

Critical Pitfalls to Avoid

• Do not delay wound washing while seeking medical care - this is the single most important immediate intervention 2
• Do not assume dried blood eliminates all risk - while risk is substantially reduced, it is not zero 1
• Do not skip follow-up testing even if PEP is declined or the initial risk assessment suggests low probability 1
• Do not focus solely on HIV - hepatitis B is a much more infectious bloodborne pathogen in this scenario 1

Source Individual Testing (If Possible)

If the source individual can be identified and consents to testing: 1

• Rapid HIV testing of the source can guide PEP decisions
• Hepatitis B and C testing of the source informs your management
• However, do not delay your own evaluation or PEP initiation while attempting to locate or test the source person 1