Types, Accuracy, and When to Take One
If you think you might be pregnant, a pregnancy test is usually the first step. But with so many types on the shelf and conflicting advice online, it can be confusing to know which test to use, when to take it, and how reliable the result really is.
This guide explains:
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How pregnancy tests work
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The different types available
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When to test for the most accurate result
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What can cause false positives or false negatives
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When to follow up with your GP or midwife
How Pregnancy Tests Work
All pregnancy tests detect a hormone called human chorionic gonadotropin (hCG). This hormone is produced by the placenta shortly after a fertilised egg attaches to the lining of the uterus.
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hCG starts to appear in your blood and urine around 6 to 12 days after conception
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Levels rise quickly in early pregnancy, roughly doubling every 2 to 3 days
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Tests are designed to detect hCG once it reaches a certain level
Types of Pregnancy Tests
There are two main types: urine tests and blood tests.
1. Home Urine Tests (Over the Counter)
These are the tests you buy at a pharmacy or supermarket. They are convenient, private, and can be used at home.
How they work:
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You hold a test stick in your urine stream or dip it into a collected sample
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The test detects hCG in your urine
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Results appear in a few minutes, usually as lines, a plus sign, the word "pregnant," or "not pregnant."
Types of home tests:
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Standard tests: Show a result after a missed period
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Early detection tests: Claim to detect pregnancy a few days before your period is due
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Digital tests: Display words like "pregnant" or "not pregnant" instead of lines, which some people find easier to read
All work in a similar way. The main difference is sensitivity, how low a level of hCG they can detect.
Accuracy:
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When used correctly and after a missed period, home urine tests are about 97 to 99% accurate
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Accuracy drops if you test too early or do not follow the instructions
2. Blood Tests (Done by a GP or Pathology Lab)
Blood tests are ordered by your doctor and processed in a lab. They measure hCG in your blood.
Two types of blood tests:
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Qualitative hCG test: Simply answers "yes" or "no" to whether hCG is present
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Quantitative hCG test: Measures the exact amount of hCG in your blood
Why a blood test might be used:
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To confirm pregnancy earlier than a urine test can
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To check that hCG levels are rising properly in early pregnancy
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If there is concern about an ectopic pregnancy or miscarriage
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If a urine test result is unclear
Accuracy:
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Blood tests can detect hCG earlier than urine tests, sometimes as early as 6 to 8 days after ovulation
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They are very accurate when done at the right time
When to Take a Pregnancy Test
Timing matters. Testing too early is the most common reason for a false negative result.
Best time to take a home urine test
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On or after the first day of your missed period
This gives hCG time to build up to a level the test can detect -
First thing in the morning
Your first morning urine is more concentrated, which makes hCG easier to detect, especially if you are testing early
If you do not track your cycle
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Wait at least 10 to 14 days after you think you may have conceived
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If you are not sure, wait until you notice other early signs such as breast tenderness, nausea, or fatigue, then test
If you test early and get a negative result
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It may simply be too early
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Wait 2 to 3 days and test again
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If your period still does not arrive and you continue to have symptoms, see your GP
If you get a positive result
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Book an appointment with your GP or midwife to confirm the pregnancy and start antenatal care
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You do not usually need to take multiple tests once you have a clear positive
Many people notice symptoms like fatigue, nausea, or breast tenderness around the time they take a pregnancy test. Alongside rest, some find that using supportive products such as a pregnancy pillow or comfortable maternity sleepwear (for example, from Sleepybelly) can help improve comfort during this early stage.
How to Use a Home Pregnancy Test Properly
Follow the instructions on the box exactly. Each brand is slightly different, but general steps include:
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Check the expiry date on the box
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Collect a urine sample in a clean container, or hold the test stick in your urine stream as directed
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Wait the recommended time, usually 3 to 5 minutes
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Read the result within the time window stated in the instructions
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Reading too early or too late can give incorrect results
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Do not reuse the test
If the result is unclear, faint, or confusing, take another test in a day or two, or see your GP for a blood test.
Understanding Your Result
Positive Result
A positive result means hCG has been detected. This almost always means you are pregnant.
What to do next:
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Book an appointment with your GP or midwife
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Start folic acid if you have not already (usual dose is 0.4 to 0.5 mg daily, see Folate and pregnancy)
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Stop alcohol and review any medications with your clinician
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Avoid high risk foods (see Foods to avoid when pregnant)
Once you have a positive result and start to prepare for early pregnancy, practical comfort aids like a pregnancy pillow, maternity pyjamas, or soothing magnesium body cream (Sleepybelly offers these products designed for pregnancy comfort) can help you rest better as your body adjusts.
Negative Result
A negative result means hCG was not detected, or the level is too low to measure.
Possible reasons:
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You are not pregnant
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You tested too early
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Your urine was too dilute
What to do next:
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If your period does not arrive in a few days, test again
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If you continue to have symptoms or are concerned, see your GP
Faint Line or Unclear Result
A faint line usually still counts as positive, even if it is very light. This can happen if hCG levels are still low because you tested early.
What to do:
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Repeat the test in 48 hours; the line should get darker as hCG rises
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If still unclear, see your GP for a blood test
Evaporation Line
Sometimes a faint line appears after the test has dried. This is called an evaporation line and is not a positive result.
How to avoid confusion:
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Read the result within the time window stated in the instructions
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Do not read the test hours later
What Can Cause a False Positive?
False positives are rare, but they can happen.
Possible causes:
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Recent pregnancy loss or termination
hCG can remain in your system for several weeks -
Certain medications
Some fertility treatments contain hCG -
Rare medical conditions
Such as certain tumours that produce hCG -
Chemical pregnancy
A very early miscarriage that happens soon after implantation -
Faulty or expired test
If you get a positive test but then start bleeding heavily, or your GP cannot confirm pregnancy, follow up promptly for assessment.
What Can Cause a False Negative?
False negatives are more common than false positives.
Possible causes:
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Testing too early
hCG has not yet built up to detectable levels -
Dilute urine
Drinking lots of fluids before testing can weaken the hCG concentration -
Not following instructions
Reading the test too early or too late, or using an expired test -
Ectopic pregnancy
hCG may rise more slowly, so levels might be lower than expected
If you have a negative test but your period does not arrive, and you have symptoms, test again or see your GP.
When to See Your GP or Midwife
After a positive test
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Book an appointment within a week or two to confirm pregnancy and begin antenatal care
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Your GP may do a urine test, blood test, or arrange an early ultrasound
After a negative test
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If your period is more than a week late and you still have symptoms, see your GP
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If you have irregular cycles or are unsure of dates, your GP can help work out timing
If you have symptoms that worry you
Even before testing or while waiting for an appointment, seek care urgently if you have:
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Heavy bleeding or severe abdominal pain
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Shoulder tip pain or fainting
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Symptoms of ectopic pregnancy (one-sided pain, dizziness, bleeding)
Quick Checklist: Getting the Most Accurate Result
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Wait until the first day of your missed period, or at least 10 to 14 days after possible conception.
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Use the first morning urine if testing early.
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Follow the test instructions exactly.
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Read the result within the time window stated on the box.
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If negative, but your period does not arrive, test again in 2 to 3 days.
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If positive, book a GP or midwife appointment to confirm and start care.
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If you have pain, heavy bleeding, or feel unwell, seek urgent medical advice.
Conclusion
Pregnancy tests are simple, reliable tools when used at the right time and in the right way. Home urine tests are accurate from the first day of a missed period, and blood tests ordered by your GP can detect pregnancy even earlier. Testing too early is the most common reason for a false negative, so if in doubt, wait a few days and test again.
Once you have a positive result, the next step is to see your GP or midwife to confirm the pregnancy, start antenatal care, and begin looking after yourself and your baby. If you are ever unsure about a result, have symptoms that worry you, or just need reassurance, do not hesitate to contact your healthcare provider.
Remember to be kind to yourself and rest when you can. Small practical changes, including using pregnancy specific comfort products such as Sleepybelly’s pregnancy pillow or maternity pyjamas, can make a meaningful difference to your wellbeing during this early stage.
Sources / References
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Better Health Channel – Pregnancy testing
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The Bump – What is hCG / hCG levels by week
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Pregnancy, Birth and Baby – Folate and pregnancy
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IVF Australia / Melbourne IVF – Taking a pregnancy test and tell‑tale signs you’re expecting
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Pregnancy, Birth and Baby – Foods to avoid when pregnant
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The Royal Women’s Hospital – Your first pregnancy check-up
