What Is the HIV Window Period?

The window period is the time between HIV infection and when a test can reliably detect it.

Window Periods by Test Type

• HIV RNA (viral load): 9–11 days — earliest detection
• 4th-generation antigen/antibody: 18–45 days
• 3rd-generation antibody only: 23–90 days
• Rapid oral test: 23–90 days

Why It Matters

• Testing too early = false negative
• If exposed, test at appropriate window
• Re-test at 3 months for definitive result

If You Think You Were Exposed

• See a provider immediately about PEP (must start within 72 hours)
• Test at appropriate window period
• Use protection until confirmed negative