Nature’s Challenge To Home Pregnancy Test Accuracy
Home Pregnancy Tests Expert posted in Pregnancy Tests on April 2nd, 2007
If a woman asks her doctor about home pregnancy test accuracy, she could get a lesson focused on test results. Some test results deliver findings that are what scientists call “false negatives.” Such false negatives can diminish a woman’s hope for home pregnancy test accuracy. Yet such false negatives do not have the same effect as false positives. A woman using a home pregnancy testing kit would not want to be given ill-founded evidence that she has become pregnant. Her hopes for a child would soon be crushed, following a confirmatory test. Perhaps that is why nature has no design for creation of a false positive result.
Certain laws of nature helped with the development of the home pregnancy test. The laws of nature demand that any woman must periodically release a stream of urine. Scientists have found a way to achieve in-home detection of a particular hormone in that urine stream. They have thus laid the groundwork for creation of an easy-to-use home pregnancy test.
Yet the science behind that home kit does not ensure home pregnancy test accuracy. In fact, the very nature of each woman’s hormonal changes limits all planned improvements in home pregnancy test accuracy. In order to appreciate those limits, one must gain a fuller understanding of the hormonal changes that both precede and follow the actual conception of an infant.
During the course of a woman’s monthly cycle, the estrogen level in her bloodstream will rise. That tells her body to prepare her uterus for the possible implantation of a zygote. As her estrogen level rises, the woman begins to produce progesterone as well as estrogen. The duration of time during which a woman has that combination of high estrogen and high progesterone levels depends in large part on her desire for passionate sex.
If the woman takes part in intercourse, and if a sperm then fertilizes a released egg, that fertilized egg could well become implanted in the woman’s uterus. Such an implantation would lead to the production of human chorionic gonadotropin (HCG) by the woman’s placenta. That HCG would then show-up in the woman’s urine.
The above facts lay out the science behind the home pregnancy test. Those facts do not, however, reveal how one could develop a consistently accurate home pregnancy test. Those facts focus on the science behind the qualitative test for HCG. They say nothing about the nature of a quantitative test.
Yet the very nature of a pregnant woman’s HCG level makes clear the advisability of performing a quantitative test. Immediately following conception, a woman’s HCG level challenges any dreams for home pregnancy test accuracy. That’s because immediately after conception the HCG level in a woman’s serum does not approach the magic figure of 20 to 25 mIU per ml.
Immediately after conception, a woman has an HCG level of 5 to 10 mIU per ml. That low level will not produce detectable levels of HCG in the woman’s urine. Consequently, that low level of HCG can not be detected by the in-home pregnancy test.
The above facts underscore the futility of going after vast improvements in home pregnancy test accuracy. A woman about to conduct an in-home test must consider the very real possibility that her test could produce a false negative result.
What would be the meaning of a false negative result? It would represent a finding that has bolstered an erroneous belief, a belief that no trace of a particular substance (in this case HCG) exists.