Home Pregnancy Test vs. Hospital Results: the Discrepancy

The results of a home pregnancy test differ from those obtained at a hospital?

My menstrual cycle is usually 28 days long.
I had sexual intercourse on the night of August 31, so my period was expected to arrive on September 15, but it hasn't come yet.
This morning, September 19, I used a home pregnancy test, and after 3-5 minutes, there was only one line.
However, after 10 minutes, a second faint line appeared.
In the afternoon, I went to the hospital for a pregnancy test, and there was only one line on the test strip.
An ultrasound was not performed, and the doctor only prescribed medication and told me to wait for my period.
What is the likelihood that I am pregnant?

Xiao Ai, 20~29 year old female. Ask Date: 2017/09/19

Dr. Huang Jianzhong reply Obstetrics and Gynecology

The menstrual cycle is typically 28 days.
I had sexual intercourse on the night of August 31, and my period was expected to arrive on September 15, but it hasn't come yet.
This morning, September 19, I used a home pregnancy test, and after 3-5 minutes, there was only one line.
After 10 minutes, a second faint line appeared, which was almost indistinguishable.
In the afternoon, I went to the hospital and used a test strip, which also showed only one line.
An ultrasound was not performed, and the doctor only prescribed medication and told me to wait for my period.
What is the likelihood that I am pregnant? Answer: The hospital test strip showed only one line, indicating that the likelihood of pregnancy is low.

Reply Date: 2017/09/19

More Info

When it comes to understanding the discrepancies between home pregnancy tests and hospital results, it's essential to consider several factors that can influence the accuracy of these tests.
Home pregnancy tests (HPTs) are designed to detect the presence of human chorionic gonadotropin (hCG) in your urine. This hormone is produced shortly after a fertilized egg attaches to the uterine lining, typically around six days post-ovulation. For someone with a regular 28-day cycle, ovulation usually occurs around day 14, meaning that if conception occurred during intercourse on August 31, you would expect to see elevated hCG levels by September 7 or 8.
In your case, you tested on September 19, which is about five days after your expected period. The fact that you saw a faint line on the home test could indicate a low level of hCG, which might suggest early pregnancy. However, the faintness of the line can also be attributed to several factors, including the sensitivity of the test, the concentration of your urine, or the timing of the test in relation to your ovulation and implantation.

When you went to the hospital and received a negative result on the urine test, it could be due to a few reasons. Firstly, the hospital test might have a different sensitivity compared to your home test. Some hospital tests are designed to be more specific and may require a higher concentration of hCG to show a positive result. Additionally, if you were tested later in the day when your urine was more diluted, this could also lead to a negative result.

Another important aspect to consider is the timing of the test. If you tested too early, there may not have been enough hCG in your system to trigger a positive result. It's also worth noting that some women experience a phenomenon known as a "chemical pregnancy," where an embryo may implant and produce hCG but fails to develop further, leading to an early miscarriage and a subsequent negative test.

Given your situation, it is advisable to wait a few more days and retest at home, preferably with the first morning urine, which is typically more concentrated and may yield a more accurate result. If your period does not arrive within a week, or if you continue to have faint lines on home tests, it would be prudent to follow up with your healthcare provider for further evaluation, which may include a blood test to measure hCG levels more accurately.

In summary, the discrepancy between home pregnancy tests and hospital results can stem from differences in test sensitivity, timing, and urine concentration. If you suspect you might be pregnant, it’s essential to monitor your symptoms and consider retesting or consulting with your healthcare provider for further guidance.

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