Making sense of your HCG blood test report - a guide for IVF patients

One of the most important blood tests for IVF patients is the HCG test .

This is done two weeks after the embryo transfer , to find out whether the embryo implanted or not – and tells us if your IVF was successful or not . Obviously , a lot rides on it , and whenever patients get their report , the first thing they want to know is if it is positive or negative.

Now making sense of the HCG report is extremely easy , because HCG ( for all practical purposes ) is produced only by the placenta during pregnancy . This means if it positive , you are pregnant - and if it is negative , this means you are not pregnant .

However, we find many patients have a hard time interpreting the HCG level , and this is true for multiple reasons .

The first problem is the lab report format, which is very unfriendly. While the report is medically accurate , it’s full of numbers ( for example, the normal ranges during the pregnancy). This makes it hard for patients to know what the expected normal range for them should be, because HCG levels rise so rapidly during pregnancy , and the lab has to include all the ranges when reporting , because it doesn't know how many weeks pregnant the patient is . Patients only care about their value, and often can’t even find this on the report.

Another big problem with interpreting the HCG level is the fact that there is such a wide range of normal values. This is because HCG levels rise exponentially , which means they double every two days , and the level rises from 300 mIU/ml to 1000 mIU/ml in 4 days !

Patients don’t understand this, because they are much more used to interpreting simple blood tests such as blood sugar levels , or hemoglobin levels , which usually remain pretty much stable over time .

A big problem is also that patients are innumerate, and don't understand how to make sense of numbers . For example, they don’t understand decimals, and when the laboratory reports the HCG level as being less than 0.567 ( which means it’s negative because it’s less than 1), they get confused .

Some patients naively believe that negative equals zero, and that the presence of any HCG in their body means that they must be pregnant – after all, how did this HCG show up if they aren’t pregnant ?

The problem is that a negative HCG level causes a lot of frustration and heartache. It’s hard to come to terms with the truth, and patients are very hopeful that if they repeat it again, it may become positive.

The problem is that false hope can be cruel, and if the HCG level ( as done from a reliable lab ) 12 days after the embryo transfer is negative , this means your cycle has failed , and there's no point in wasting money on repeating the test again .

Another major area of confusion is the weeks of pregnancy reported as part of the normal range on the printed area . Patients are confused , and don’t understand the difference between the menstrual age ( as calculated by the duration from the last menstrual period, LMP) vs embryonic age ( the actual age of the embryo).

While a negative HCG is easy to interpret, a positive HCG is harder to decipher, because a single value means little. We need to repeat the test, to ensure it is doubling every 2-3 days, to confirm that the placental cells are growing well, which suggests a healthy, viable pregnancy