How to Take a Home Pregnancy Test (and Get an Accurate Result)

Home pregnancy tests detect a hormone called human chorionic gonadotropin (hCG), which your body starts producing once a fertilised egg implants in the uterus. Getting an accurate result comes down to understanding two things: when hCG is actually detectable, and the small but common mistakes that lead people to test too early or misread a result.

When can a test actually detect pregnancy?

hCG typically becomes detectable in urine around 10 days after conception at the earliest, though it varies by person and by how sensitive the specific test is. Testing from the first day of a missed period gives the most reliable result for most tests. Testing earlier than that increases the chance of a false negative — not because you're not pregnant, but because hCG levels simply haven't risen high enough yet to trigger a positive result.

"Early result" tests: what the sensitivity numbers mean

Tests marketed as detecting pregnancy "days before your missed period" work by having a lower hCG detection threshold — often 10 or 25 mIU/ml compared to standard tests' 25 mIU/ml threshold. A lower number sounds more sensitive, and technically is, but even the most sensitive tests can still miss an early pregnancy if you test too soon, since hCG levels roughly double every 48-72 hours in early pregnancy — testing a couple of days earlier can be the difference between a faint line and no line at all.

Common mistakes that cause false negatives

• Testing too early — by far the most common cause, discussed above.
• Diluted urine — drinking a lot of fluid before testing dilutes hCG concentration. First-morning urine is more concentrated and gives the most reliable reading.
• Not waiting the full development time — most tests need several minutes to develop fully; reading too early can miss a faint but genuine positive line.
• Reading after the result window — evaporation lines can appear well after the recommended reading time and are sometimes mistaken for a faint positive. Always read within the time stated in the instructions.

What a faint line means

Any visible line, however faint, generally indicates a positive result — pregnancy tests aren't designed to get "more positive" with a darker line as pregnancy progresses in a way that's meaningful to interpret at home. A faint positive is still a positive. If in doubt, testing again in 2-3 days (when hCG levels will have risen further) usually gives a clearer result.

What to do after a positive result

Book a GP or midwife appointment to begin antenatal care — this is usually called your "booking appointment" and ideally happens by around 10 weeks of pregnancy. You don't need to wait for a scan to confirm the pregnancy before booking; a positive home test is enough to start the process.