Can a Pregnancy Test be False Negative
Most women will agree that pregnancy test is the greatest or at least the most useful and convenient humankind’s invention. Only one dollar or two, a few minutes, in any place, anytime you can get the answer to the exciting question: pregnant or not. Could our grandmothers dream about that?!
In general, pregnancy test is, undoubtedly, the thing! Nevertheless, it has one essential disadvantage: it quite often gives false result. In addition, in most case it is false negative – when pregnancy in fact is, but the test gives false result. What are the reasons of this?
Usually on the first day of missing a period the level of hCG, which is produced by chorion, is higher enough to be detected by a test’s reagent. In some cases it is possible early, and in some later. Nevertheless, in most cases it is – only by the time of the beginning of coming period. That is why, you find in the test’s instruction the recommendation to use the test only after period’s delay and redo it in a few days – to get results that are more reliable. If the hCG level in urine is not high enough by the time of testing (less than 20-25mlU/ml), so you will get false negative result.
The accuracy of a pregnant test on early period is higher if the urine for test is more concentrated. That is why pharmacists advise to use first urine in the morning for the test – during the night the concentration increases, and there are more chances, that the reaction strip will “catch” hCG. If you take diuretic drug, that makes you urinate even at night, or you have drunk too much water before the testing, so you cannot rely on the early morning urine. In later period, the level of gonadotrophin in urine increases so much, that the test gives the true result, which does not depend on the testing time. However, if there are only 12-14 days have passed after the conception that plays an important role in getting the true results.
Breaking the Rules
These and other obligatory rules and conditions of using the test are depicted in every instruction not without purpose. Only when you follow all the instructions you can get the true result. If you have broken one of them, the test can be false negative. See the manual and conform to the instruction directly.
Almost all modern pregnancy tests are rather accurate, but it cannot be left out that you get the substandard, overdue or spoiled test, which has being kept in defective conditions. Repeated in a few day test will make this method more informative.
Unfortunately, among reasons of false negative test there are some terrible reasons – it is blighted ovum (embryo does not develop) or anembryonic pregnancy, level of hCG does not increase, as it must be during normal pregnancy. Sometimes hCG is not produced enough at the beginning of a pregnancy when there is threatened miscarriage, in this situation the test can also be false negative. The wrong function of kidneys also can effect on the results of the test. That is why if the pregnancy tests give negative results and the periods do not come you should consult the doctor to find out the reason.