In general, the pregnancy test is definitely a thing! However, it has one significant drawback: it often shows an erroneous result. And in the vast majority of cases it is false-negative - when the actual pregnancy test shows its absence. What could this be the reason?
Very Early Testing
Usually, by the first day of delay, the level of hCG produced by the chorion is already increasing enough to be able to fix the test reagent. In some cases, this is possible a little earlier, in others later. But still in the vast majority of cases - only to the beginning of the expected monthly. Therefore, in the instructions for the tests you will meet the recommendation to conduct the test only after the delay of the monthly and repeat it in a few days - for a higher reliability. If the level of hCG in urine at the time of testing is not yet high enough (less than 20-25 mE / l), then you will get a false negative result.
Too dilute urine
The confidence of the pregnancy test in early terms is higher the more concentrated urine is used for testing. Therefore, pharmacists recommend to spend it in the morning with the first portion of urine - for the night its concentration increases, and there is more chance that the reactive band will "catch" hCG. If you take diuretics, which forces you to urinate even at night, or before testing you drank too much liquid, then you should not even rely on morning urine.
In later terms, the level of gonadotropin in the urine already increases so much that the test shows a true result regardless of the time it takes. But if only 12-14 days have passed since conception, this condition plays a big role in obtaining truthful results.
Violation of rules
These and other mandatory rules and conditions for conducting tests are not without purpose described in each instruction. Because only with their observance can you count on a reliable result. If you violated any of them, then the test may well be false-negative. Read the manual and follow the instructions strictly.
Almost all modern pregnancy tests differ fairly high reliability, but it is still possible that you got a low-quality, stitched or spoiled test, which was stored in violation of conditions. Repeated test in a few days depends on the informative nature of this method. Unfortunately, among the causes of a false negative test, there may be tragic ones - it is a frozen (undeveloped) pregnancy or anembrionia, in which hCG does not increase, as is usually the case with a normally developing fruit. Sometimes HCG is produced in insufficient quantities when there is a threat of miscarriage at the earliest possible date, and then the result may also be false-negative. The results can also affect the functioning of the kidneys.
Therefore, if a pregnancy test that has been repeatedly performed shows a negative result, but the next monthly one does not occur, you should definitely contact the gynecologist to find out the reason.