When a woman becomes pregnant, her body begins to produce hCG, a hormone which is released into the blood where its concentration rises over time. The SELFCheck Pregnancy Blood Test uses a pair of specific antibodies to detect this hCG hormone and gives a positive result when the hCG level in the blood is higher than 25 IU/L as determined against the World Health Organisation (W.H.O) reference standard. This is the same hormone detected in urine pregnancy test kits.
Unlike urine pregnancy tests where it is advised to use an early morning urine sample, you can use a blood test at any time of the day or night. The SELFCheck Pregnancy Blood Test can detect pregnancy earlier than most urine tests because the hCG hormone produced in the placenta is first released into the blood and then into the urine.
Yes! But the finger-prick test isn't difficult either. The SELFCheck Pregnancy blood test has been independently assessed by scientists and doctors to prove that they provide reliable results, meet UK and EU regulations and designed to be easy to use.
Comparison of the SELFCheck Pregnancy Blood Test with a reference laboratory method shows an overall agreement of at least 98%. Although this test is accurate, all pregnancy tests may give a small number of false positive or false negative results. The same device used by SELFCheck is also used in hospitals to provide a quick and reliable result.
If the result is positive, you should consult your doctor to discuss pregnancy and the next steps. Early prenatal care is important for a healthy pregnancy. Please take into consideration that not every pregnancy proceeds to term and the risk of miscarriage is highest during the first couple of months. For this reason, it is possible to get a positive result with an early pregnancy test but find that a subsequent scan at 5 to 6 weeks is negative. The level of hCG can remain elevated for some time after a miscarriage.
If the test is negative, it is most likely that your blood either doesn't contain hCG or very low levels of hCG (the test detects hCG concentration as low as 25 IU/L) and you are unlikely to be pregnant. However, you may have miscalculated the date of your period, especially if you have irregular periods. If your period does not start within a week, repeat the test. If you still get a negative result and your period has not started, you should speak with your doctor. A late period could be caused by other reasons.
Providing the instructions have been followed as written and the correct amount of blood and diluent has been added then your result will be reliable. Although the instructions say that any line, no matter how faint, is a positive result, if you find that the test line is barely visible then you are testing far too early. Check again in about a week or two and you should see an obvious pink line if you are pregnant.
An invalid result is recorded when the control line doesn't appear in the results window. The most common reason for an invalid result is due to not enough drops of diluent solution being added - this can easily be fixed by adding a further 2 drops of diluent.
Other reasons include adding the blood or diluent to the wrong place or not adding enough or adding too much blood. Always read the instructions carefully before touching the components or starting the test.
The SELFCheck Pregnancy Blood Test is a very sensitive test and can detect a rise in the pregnancy hormone (hCG) before the routine urine tests that are often used by your doctor. Sadly, the rate of miscarriage is very high during early pregnancy occurring in around 10% of women under 30 and 50% of women over 45 years old. This means that you may get a positive result with a very sensitive pregnancy test but a negative result with a scan or urine or blood test later on - see https://www.nhs.uk/conditions/miscarriage/causes/.
The Pregnancy Blood Test is used in hospitals and also meets all the regulatory requirements for self test diagnostics (IVDD 98/79EC) which means that it has been independently reviewed by clinicians and scientists, shown to provide reliable results and is easy to use. It is accepted by doctors that all medical tests, whether those performed in the laboratory, or at home, may have a risk of a small proportion of false positive or negative results.
An 'evaporation line' occurs when some pregnancy tests are not used exactly as written in the instructions and are sometimes seen as a grey or white streak where a positive result should appear. This may happen if the test kit is out of date, stored incorrectly, not enough sample is added or you wait too long to check your result.
If you are pregnant you will see a pink line, although this might be very faint if you test too early. If you see a very faint line, check again in a week or too and if you are pregnant you will see an obvious pink line.
The results are accurate as long as the instructions have been carefully followed. Certain drugs containing hCG, or drugs used in combination with hCG (such as Pregnyl, Porfasi, Pergonal) and rare medical conditions may lead to a false positive result. Alcohol, analgesics, antibiotics, birth control pills, hormone therapies containing clomiphene citrate (such as Clomid, Serophen) or painkillers should not affect the test result.
The test may show a false positive result if you have had a miscarriage, abortion or have given birth within the past 8 weeks. This is due to the test detecting hCG still remaining in your blood system.
In the blood, hCG reaches these levels sooner than in the urine. A blood test can detect hCG about 11 days after conception and about 12-14 days after conception by a urine test (americanpregnancy.org). It is important to keep in mind that the earlier you test with a blood or urine pregnancy test, the greater the chances of a false positive or negative result.
Most pregnancy tests are very reliable being around 97 to 99% accurate for the detection of hCG both at home or in a hospital laboratory, but that does mean at least 1 in 100 people may get a false positive or negative result.
The main reasons for these false positive and negative results are not issues with the tests or technology but more so to do with how early the test was used, how much hCG was being produced at the time, presence of interfering factors and whether the test was unknowingly used incorrectly.
Testing before the first missed period is possible with some of the more sensitive urine and blood tests but the number of false negative and positive results can be high due to very low levels of hCG at the time of the test, or if the pregnancy does not continue. It is important to be aware of these risks and the potential for concern or disappointment if you do decide to test before your first missed period.
It is not unusual, even with hospital laboratory tests, for tests from different manufacturers, different batches from the same manufacturer or even different hospital labs using the same test, to give differing results when the levels of hCG are very close to the detection limit of the tests.
All SELFCheck tests, including the pregnancy blood test, undergo extensive user trials to show that the test can be used successfully and get a reliable result. At SELFCheck we also collate and analyse any reported incident where a user has not been able to get a result. Although these incidents are quite rare, it is important to us that any issues are followed up and each customer receives a personal reply when they contact SELFCheck directly. In almost all cases where there has been an issue, it is usually obvious that the instructions haven't been followed correctly, even where the user of the test believes that they have done so.
Evaluation samples of each test are retained from each batch in order to follow up any concerns from users with further quality control checks at our laboratory and those of the manufacturer. It has always been the case that whenever these retained samples have been checked that we are unable to reproduce the issues found by the user.
We are constantly looking at ways to improve the information provided in our instruction leaflets to make use of the tests as obvious to as many people as possible and we welcome feedback from our customers to help us to do so.
Indentation lines sometimes appear on some urine based pregnancy tests and are usually due to the way in which the antibodies that detect the hCG are applied to the test strip. These indentation lines may become visible with some brands of urine tests particularly when the hCG level is very low, showing as a very thin faint line that could be misinterpreted as a positive result. The best advice is that if you see a very faint line (or a 'white' line) then the hCG level must be very low and you will need to check again around a week later to confirm a positive result - if you are pregnant, the levels of hCG by then should be quite high and give an obvious positive result!