The short answer is Yes, hCG blood tests are used for confirming the results of “at home urine pregnancy tests”, and there’re many reasons why urine pregnancy tests may fail to present accurate pregnancy detection.
Why Pregnancy test in urine are not accurate for detection of pregnancy?
In fact, hcg hormone, the principal pregnancy hormone are secreted within a week after successful inoculation, therefore it can be detected in hcg blood tests within a week of pregnancy while it takes another week to increase in amount to the level it can be detected in urine pregnancy tests.
Thus, using pregnancy home tests to detect hcg hormone in urine is accurate and sensitive but it’s not specific enough to detect only hcg but could be prune to interference of other biochemicals in the urine as well as if the woman has urinary tract infection it can show false positive (faint purple line) in the urine pregnancy test.
Do you need hcg blood test to confirm positive pregnancy test in urine?
Yes, you must confirm positive urine pregnancy test if the second line is faint and not clearly colored blue or purple, that’s because the faint test line in the pregnancy strip could be a sign of very early pregnancy detection or can be a sign of interference. in other words you must get two distinctive lines n the pregnancy strip to make sure it’s real pregnancy.
While at home pregnancy tests uses urine samples which is non-invasive and cheaper than blood test, but in some cases, the urine pregnancy tests give false or unclear results for many reasons, therefore, you must get tested in blood for hcg pregnancy test to confirm the finding in the already done urine test.