Is it true that for some people a HPT will give negative result even if they are pregnant by several weeks?

Yes, it is true that for some people a home pregnancy test (HPT) may give a negative result even if they are pregnant by several weeks. There are a few reasons why this might happen:

- The HPT is not sensitive enough to detect the low levels of human chorionic gonadotropin (hCG) hormone in the urine early in pregnancy. HCG levels rise rapidly in early pregnancy, but they may not reach detectable levels on a HPT until several weeks after conception.

- The HPT is not used correctly. Home pregnancy tests must be used according to the package instructions in order to get accurate results. This includes using the first morning urine, following the directions for holding the test strip, and waiting the recommended amount of time before reading the results.

- The HPT is past its expiration date. Expired HPTs may not work properly, and they may give false negative results.

- The person is taking medications that can interfere with HPT results. Certain medications, such as some fertility drugs and diuretics, can cause false negative results on HPTs.

- The person has an ectopic pregnancy. In an ectopic pregnancy, the fertilized egg implants outside of the uterus. This type of pregnancy can produce hCG levels that are too low to be detected on a HPT.

If you think you may be pregnant but you have a negative HPT result, it is important to see your doctor for a blood test to confirm or rule out pregnancy. A blood test can detect hCG levels even when they are very low, so it is more accurate than a HPT for early pregnancy detection.