HIV PCR Test

An HIV PCR test — a nucleic acid test — looks for the virus's genetic material in a sample of blood drawn from the arm, rather than for your immune system's response to it. Because it looks for a different thing, it can give an answer earlier after a possible exposure than an antibody test can. It is the more expensive option and it does not remove the need for follow-up: a negative PCR early on narrows the picture rather than closing it. The sample goes to a laboratory, and a doctor goes through the report with you rather than handing you a printout.

• Anyone whose doctor has recommended it after discussing a specific exposure
• Anyone who needs a clearer answer sooner than an antibody test can give one
• Anyone following up a result that needs clarifying
• Anyone testing as part of a plan already agreed with a clinician

1. Day 0 – 10

   Too early even for PCR. There is usually not yet enough virus in the blood to detect. Within 72 hours of an exposure, PEP is the time-critical conversation; the testing plan comes after it.

2. Day 10 – 33

   Where PCR earns its cost. This is the period in which it can detect the virus's genetic material while an antibody test would still be blank. A positive is acted on immediately; a negative narrows the picture but is not yet an all-clear on its own.

3. Day 33 – 45

   Past PCR's best use. By this point a fourth-generation antigen/antibody lab test is generally the better instrument, and it is typically conclusive by day 45. The doctor will usually move you onto that rather than repeat the PCR.

4. Day 45 – 90+

   Confirmation. A negative fourth-generation lab test at 45 days is conclusive for that exposure; a rapid antibody test reaches the same point at 90. Which of these applies to you depends on what you were tested with, and the doctor will tell you plainly.

• From about 10 days after a possible exposure — earlier than that, there is usually not enough virus present to find.
• Between roughly 10 and 33 days is the window in which a PCR is most useful; past that, an antigen/antibody lab test is generally the better instrument.
• A negative PCR is not a final all-clear on its own. Plan on a follow-up antibody test at the interval the doctor sets.
• If the exposure was within the last 72 hours, ask about PEP before you plan any testing at all.

• This is a draw from a vein in the arm, so wear something with a sleeve that rolls up easily.
• No fasting is needed for this test, and you can eat and drink as normal.
• The result is not same-day — check the turnaround above before planning around it. You collect it by logging in; we will not send it by email, SMS or LINE.