Pregnancy tests and sensitivity
Pregnancy tests detect the hormone chorionic gonadotropin (hCG) in the urine. hCG is naturally produced by the woman's body and is present in the early stages of pregnancy. Generally, hCG is doubled every 72 hours.
|Levels of hCG during pregnancy|
|3 weeks after the last period:||5 – 50 mIU/ml|
|4 weeks after the last period:||5 – 426 mIU/ml|
|5 weeks after the last period:||18 – 7,340 mIU/ml|
|6 weeks after the last period:||1,080 – 56,500 mIU/ml|
|7-8 weeks after the last period:||7,650 – 229,000 mIU/ml|
|9-12 weeks after the last period:||25,700 – 288,000 mIU/ml|
|13-16 weeks after the last period:||13,300 – 254,000 mIU/ml|
|17-24 weeks after the last period:||4,060 – 165,400 mIU/ml|
|25-40 weeks after the last period:||3,640 – 117,000 mIU/ml|
|HCG levels in non-pregnant women:||less than 5 mIU/ml|
|Post-menopausal hCG levels:||about 9.5 mIU/ml|
As you can see in the above table, hCG levels steadily increase from conception to approximately 10-12 weeks gestation and then tend to stabilize or even drop. That is the reason why, in the first trimester of pregnancy, the symptoms are stronger and more intense. hCG levels at the beginning of pregnancy usually double every two to three days, with an increase of at least 60 percent every two days. But still, these values may differ slighthly on each woman as well as whether she is pregnant with one or more embryos.
So what does sensitivity mean to pregnancy tests?
Several girls mistakenly believe that the quality of the test depends on its sensitivity. This is not correct as the quality of the test depends on another factor called credibility or validity of the result. That is, whether you should trust the outcome of the test. The sensitivity of the test is customizable and can be changed during the test production process.
There are various pregnancy tests that measure hCG at concentrations of 10 mIU/ml or even lower. If you use such a test, you should be particularly careful with the interpretation of the result as:
- - Measurements of hCG at concentrations of up to 5 mIU/ml are insufficient to indicate pregnancy.
- - Measurements of hCG at concentrations ranging from 5 mIU/ml to 25 mIU/ml require further testing and do not guarantee pregnancy.
- - Measurements of hCG at concentrations of 25 mIU/ml and above, give more than 97% probability of pregnancy.
To put it simply, a test with a sensitivity of 25 mIU/ml and above, which you will use during the fourth week of the last period, will show you more valid results and will not make you question your pregnancy or have evidence of biochemical pregnancy, miscarriage, etc.
Remember: The presence of hCG alone is very important, but in order for the pregnancy to progress properly, hCG units must increase.
HomeTest pregnancy test and sensitivity
At which sensitivity are HomeTest pregancy tests set? HomeTest pregnancy tests (whether a strip or midstream type) have 2 values. It is the value that starts the reaction and the value that the result line is very strong.
HomeTest pregnancy tests begin the detection of the hormone from 12 units of hCG, which means that you can use them three or four days before the expected period.
In those cases where the hormone is still quite low, positive HomeTest pregnancy tests will look like this:
As you can see in the above images, the result line is barely visible (faint) as hCG values have reached 12 units. Nevertheless, the test is positive.
As the pregnancy progresses and reaches 4 weeks, which means, you have reached the day of expected period (always count your pregnancy from the first day of your period), the result line in the HomeTest pregnancy test will begin to darken as the hCG levels increase, and it will look like this:
Since hCG has increased in excess of 25 mIU/ml, pregnancy is now over 97% certain and HomeTest pregnancy tests will look like this:
So, using the HomeTest pregnancy test, you can check if you are pregnant, but also have feedback concerning the correct progression of your pregnancy. How? By taking a test every 2 days and observing the increase in hCG levels, as you can see in the picture below:
We at HomeTest.gr, always guided by the correct information and service of our customers, have our HomeTest pregnancy tests set to begin the hCG detection at 12 units but also to inform you when hCG has exceeded 25 mIU/ml and we provide over 99.99% reliability in the result.
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