The desire to get pregnant can make everything feel rushed… especially the beta hCG! Did you know it takes some time for hCG levels to rise in the body? Yes, a positive result doesn’t always appear right when implantation occurs. And that’s when the indeterminate beta hCG shows up! Let’s first better understand hCG before we delve deeper into why a beta HCG result can be indeterminate.
When hCG appears
A hormone characteristic of pregnancy, hCG appears as soon as the embryo implants in the endometrium. Its basic function is to signal the brain that pregnancy has occurred. As a result, the corpus luteum is signaled to persist and continue releasing progesterone, which maintains the endometrium so the pregnancy can continue. There are normal expected levels of hCG at each stage of pregnancy1.
Why can the beta hCG be indeterminate?
The issue occurs when the hCG test to detect pregnancy is done too early, way ahead of time. The indeterminate beta hCG happens in cases where there isn’t enough hormone for a positive result, but it’s also not low enough to be considered negative. This indeterminate beta HCG can truly tie a woman’s mind in knots!
Usually, the beta hCG test in most labs is considered positive at quantities above 25mUI in the vast majority of labs. In others, only above 50. Intermediate values between 5 and 24 mUI are considered indeterminate, even by the labs themselves. In these situations, labs themselves recommend repeating the test after 7 days.
The expectation is that HCG will double every 48 hours, meaning that in 3 days this amount should be at least 1.9 times higher than the original result. This way, it’s possible to determine the progression of the pregnancy. Even if the indeterminate beta hCG is below the threshold for a positive (25mUI), yes, it can still be considered a good sign!
Although some doctors say it’s possible to get a positive test result even within the first two days after implantation, the advisable thing is to wait at least five days after probable implantation (with or without bleeding) before taking a blood test or a pharmacy pregnancy test.
1st week: 10 – 30 mUI/mL
2nd week: 30 – 100 mUI/mL
3rd week: 100 – 1000 mUI/mL
4th week: 1000 – 10000 mUI/mL
2nd and 3rd month: 30000 -100000 mUI/mL
2nd trimester: 10000 – 30000 mUI/mL
3rd trimester: 5000 – 15000 mUI/mL
What to do to avoid an indeterminate result
To avoid an indeterminate beta HCG result, it’s advisable for the woman to wait a few days after her missed period. If a woman has a regular cycle, a five day delay is enough. But if her cycle is irregular, it’s more advisable to wait about 20 days after the day of intercourse that could have occurred during her fertile window, and then take the test.
When to repeat the beta hCG
If the beta HCG value doesn’t reach a positive threshold, you should wait four days and repeat it at the same laboratory to check its progression. If the test taken was the qualitative kind—one that shows only positive, negative, detectable, undetectable, reactive, or non-reactive—the indeterminate beta may come with a recommendation to repeat the test in a few days in the comments section. When the responsible biochemist can’t reliably determine a result, they’ll suggest a new exam. Usually, a new payment from the patient isn’t necessary. There’s an hCG calculator that helps decipher if the hormone levels are ok. Check out the hCG calculator here.
The indeterminate result with a pharmacy test is also possible! Very faint lines are considered “positive” but should also be closely monitored to see the progress of hCG, this time by the color of the test line. The darker the line, the more hCG in the body! A tip to know if a faint line may indicate pregnancy is to look at the color3. If the line is faint but has the same color as the control line, such as pink or blue, it means there is hCG in the body.
What to do when it happens?
An important point to address is when the indeterminate beta HCG result doesn’t progress. That is, when the test is repeated at the suggested interval and the value doesn’t go up, but also doesn’t drop. Or if the value drops a lot. The recommended action in these cases is to retake the test. If a positive result had already occurred, this can be a sign of a miscarriage, or that the pregnancy probably will not continue, or it is a chemical pregnancy. The important thing is to stay calm and wait a few more days for a clear result and, of course, talk with your gynecologist. Make your doctor your best ally!
See also: Pregnancy Test – Beta HCG Quantitative and Qualitative: What’s the Difference?
