Di exposure (wen HIV fit don enter your body) happen for di last 72 hours? If you test now, di test no fit tell you anytin about am yet. If your partner get HIV and e no dey take treatment wey dey work, or you no sabi im status, ask for PEP (post-exposure prophylaxis: HIV medicine wey you go take afta exposure to stop di virus) today. You must start am within 72 hours, and e dey work best within 24. How you fit get PEP
Why timing dey important
Every HIV test dey look for something wey di body or di virus dey produce afta infection. E dey take time before dat tin go build reach level wey test fit find. Until dat time, person fit get HIV and still test negative. Dat gap na di window period (di time afta infection wen test neva fit show HIV), and each kind test get im own.
So di real question no be “how dis test dey accurate?” Once di window for one test don pass, negative result don be final. Di question na “how far I don reach inside di window for dat test wen I do am?”
Week by week, test by test
“E too early” mean say di test neva fit see HIV, so negative result no tell you anytin about dis exposure. “Inside window” mean say negative result dey give you hope but e neva final. “E don final” mean say negative result show say you no get HIV from dat exposure, as long as you neva get anoda exposure since dat time.
| Afta exposure | NAT | Lab antigen/antibody (blood from vein) | Rapid antigen/antibody (dem prick finger) | Antibody, plus most self-test for house |
|---|---|---|---|---|
| Week 1 (day 7) | E too early | E too early | E too early | E too early |
| Week 2 (day 14) | Inside window | E too early | E too early | E too early |
| Week 3 (day 21) | Inside window | Inside window | Inside window | E too early |
| Week 4 (day 28) | Inside window | Inside window | Inside window | Inside window |
| Week 6 (day 42) | E don final | Inside window | Inside window | Inside window |
| Week 8 (day 56) | E don final | E don final | Inside window | Inside window |
| Week 12 (day 84) | E don final | E don final | Inside window | Inside window |
| Day 90 go front | E don final | E don final | E don final | E don final |
Dis na di CDC window periods wey di calculator dey use:
| Test | E fit see HIV from | Negative result don final from |
|---|---|---|
| Nucleic acid test (NAT / RNA) | Day 10 | Day 33 |
| Antigen/antibody lab test (4th gen, blood wey dem draw from vein) | Day 18 | Day 45 |
| Rapid antigen/antibody test (wey dem prick finger) | Day 18 | Day 90 |
| Antibody test (most rapid tests and self-tests for house) | Day 23 | Day 90 |
How negative test dey reduce estimate
Dis na one example, step by step. E use di kind sex wey get di highest risk: one time receptive anal sex (di person wey dem enter) without condom, wit partner wey get HIV and no dey take treatment. Before any test, di estimate na 1.4% (around 1 out of 72).
Negative result dey change dat number, and di later di test, di bigger di change:
- Week 1, any test: e no change. E too early for any test to see HIV.
- Week 2, negative NAT: 0.51% (around 1 out of 200)
- Week 3, negative lab antigen/antibody test: 0.7% (around 1 out of 140)
- Week 4, negative lab antigen/antibody test: 0.18% (around 1 out of 540)
- Week 6, negative lab antigen/antibody test: 0.012% (around 1 out of 8,000)
- Day 45, negative lab antigen/antibody test: 0.0014% (around 1 out of 71,000), and dis one don be final
- Week 8, negative antibody self-test for house: 0.097% (around 1 out of 1,000)
- Week 12, negative antibody self-test for house: 0.011% (around 1 out of 9,000)
- Day 90, negative antibody self-test for house: 0.0014% (around 1 out of 71,000), and dis one don be final
Di model dey careful on purpose. E dey assume say test no fit see most infections yet for di start of each window, so early negative result no dey count reach as e fit count for real life. Di methodology page explain how dis one dey work.
Most exposures dey start far lower. For man wey do vaginal sex one time without condom wit woman wey im no sabi her status, for US, di estimate na <0.0001% (around 1 out of 1,500,000). Afta negative lab test for week 4, e go be <0.0001% (around 1 out of 11,000,000).
How to choose test wey go give you early answer
- You want di earliest answer? NAT (nucleic acid test, wey dey look for di virus itself) fit see HIV from about day 10, but e cost well well and dem no dey do am everywhere.
- Di best choice for most pipo: lab antigen/antibody test (blood wey dem draw from vein). You fit find am for many places and e don be final from day 45.
- You dey use self-test for house? Most of dem na antibody tests. Dem dey useful, but dem go only be final from day 90. See HIV self-test for house.
E no bad to test early if e go help you calm down. Just plan anoda test for afta di window for dat test don close.
If you take PEP
PEP fit change di testing plan. Follow di schedule wey your doctor or nurse give you. CDC recommend HIV test about 4 to 6 weeks and 12 weeks afta di exposure.
Wetin to do now
- If e neva reach 72 hours, ask for PEP before you begin think about test.
- Calculate your timing. Count di days since di exposure and see where you dey for di table wey dey up.
- Test wen di test fit tell you something, and di best na lab antigen/antibody test from about week 3 go front.
- Test again afta di window if your first test fall inside am. Negative result afta di window, wit no new exposure, mean say you no get HIV from dat exposure.
- Any positive or reactive result (e show say HIV fit dey) need anoda lab test to confirm am. See wetin to do afta positive test.