Taking a pregnancy test is often an emotionally-charged experience, so you want to get it right the first time, particularly if you’re doing it at home.

When it comes to home pregnancy tests, the market here in Australia certainly has a lot to offer, and generally most tests will use a similar detection method which makes them all fairly accurate.

So, with so many tests to choose from, how do you know which test is the best?

How do home pregnancy tests work?

Home pregnancy tests work by detecting the presence of pregnancy hormone, human chorionic gonadotrophin (hCG), in urine.

Your body will begin to produce hCG when a fertilised egg implants in your uterus (womb). The cells which eventually become your placenta secrete hCG.

hCG takes a few weeks to build up to a sufficient level for detection – anywhere from six to 14 days post-fertilisation.

The main difference between home pregnancy tests is how sensitive they are when it comes to finding hCG. The most sensitive tests can tell you’re pregnant even if you have only a small amount of hCG in your system.

Following implantation your levels of hCG rise quickly, so testing following a missed period will generally give you the best chance at detecting hCG accurately. Most home pregnancy tests are sensitive enough to detect hCG in your urine on the first day your period is due, however sometimes patience is required.

Negative does not always mean negative if the timing is not quite right. It may simply be that the amount of hCG has not yet reached a level where it can be detected.

The main difference between home pregnancy tests is how sensitive they are when it comes to finding the pregnancy hormone, hCG.

If your period is late, and the result is negative, wait a few days then test again. You will find some pregnancy tests are more sensitive than others. The most sensitive tests can tell if you’re pregnant even if you have only the smallest amount of hCG in your system.

If you receive a negative result when you believe you may be pregnant, experts recommend waiting at least one week before taking another test. It is important that the hCG levels in your urine have time to accumulate to detectable levels.

Discovering how sensitive a pregnancy test is can be as simple as reading the information leaflet that comes in the packet. Concentrations of hCG are reported in milli-International Units (mIU) per millilitre.

The lower the miU/ml, the more sensitive a test is ie. a test with a sensitivity of 20 mIU/ml will be more sensitive than one with a sensitivity of 60 mIU/ml. Most tests will have a sensitivity of 20 – 25 miU/ml.

It should be noted that even the most sensitive pregnancy tests should be verified by a medical professional asap.

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Where can I buy a home pregnancy test?

In Australia home pregnancy tests and ovulation kits are available, without prescription, at most pharmacies, supermarkets and other general stores. Kits and tests are also available – often in bulk – online.

Some of the best selling pregnancy tests in Australia include:

  • First Response Test & Reassure Pregnancy Test
  • First Response Digital Pregnancy Test
  • First Response Instream Pregnancy Test
  • Clearblue Digital Pregnancy Test
  • Clearblue Plus Pregnancy Test Visual Stick
  • Clearblue Pregnancy Test Early Detection
  • Pregnosis Early Detection Dip & Read
  • Pregnosis Early Detection In-Stream
  • Pregnosis Digital

How to use a home pregnancy test

While the general science behind the testing is common, the way that science is conducted can vary from test to test.

It is important to read the directions carefully, because the instructions will vary from brand to brand. The more closely you follow the instructions, the more accurate your results will be.

Often it is a matter of the famous ‘peeing on a stick’, however you may be asked to catch a sample of your urine in a small cup before dipping a testing strip into your sample. Other tests require you place a small sample in a testing well using a dropper.

Home pregnancy tests have a variety of ways of delivering the results.

Most kits allow you to test at any time of the day, however some will recommend that the first urine of the day is the best for accuracy. Levels of hCG become more concentrated in your urine overnight, so if you are testing early in your cycle it might be best to try this method.

Whenever you do decide to test, it is best to try not to consume too much liquid beforehand, as this could potentially dilute the levels of hCG in your urine.

Your results can also be delivered in a variety of ways. Some home pregnancy test will show lines on the test strip and some may change the colour of your urine sample. Others may give you a positive or negative symbol on your testing strip, and newer digital tests will reveal “pregnant” or “not pregnant” in a display window.

Generally tests will give you a result in three to five minutes … which can feel like a lifetime when you’re waiting!

How accurate are home pregnancy tests?

Many doctors will use home pregnancy tests to confirm pregnancies, such is their accuracy and reliability, however, like most things there is no guarantee.

Following instructions as closely as possible will give you the best result.

False negatives: A negative result may mean that you are not pregnant, or it could simply be that you’ve tested too soon and you’re body may not be producing hCG at a detectable level yet.

False positives: These are extremely rare, but not entirely impossible. Usually if a test says ‘yes’ then you are pregnant.

The following things can sometimes trigger a false-positive result.

  • hCG-producing growths such as an ovarian tumour
  • Medications – particularly some fertility drugs which may contain hCG – may cause a false positive result
  • Protein in your urine may give a false positive result
  • A recent birth or miscarriage may also cause the presence of hCG in your system
  • The urine collecting cup is dirty – even detergent residue has been known to cause false positive results
  • The test kit is faulty – heat and moisture can impact a test’s ability to work as it should

If you are concerned with your results, consult a medical professional.

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What other ways are there to test for pregnancy?

While most practitioners are confident using home pregnancy tests, occasionally blood tests may be required.

Blood tests, which also test for hCG, are much more sensitive than a standard urine test, detecting pregnancy as soon as the egg has implanted. This may be as early as six days post-ovulation.

Blood tests can also help detect ectopic or molar pregnancies, and are useful for monitoring that the level of hCG is rising in a way that would be expected for a pregnancy to be considered healthy.

Blood testing for pregnancy is 99 percent accurate and it is for this reason that many women still choose to have a blood test done after doing a urine pregnancy test themselves at home.