Beta HCG Values: Making Sense of Them
A blood test for the presence of beta hCG is used to confirm pregnancy. The test is the most reliable method to confirm pregnancy. At your first appointment onwards the doctor will monitor the progress of the pregnancy by measuring the beta hCG levels. This is important even early in the pregnancy to ensure that nothing goes awry. The hCG actually comes from the embryo itself and it is an indication to the mother that conception has occurred. The beta hCG levels vary based on the gestational age. For instance non-pregnant women will have levels of 5mIU/ml and less but 11 to 14 days after conception the levels can rise to as much as 100 mIU/ml and will continue to double every two to three days of the pregnancy.
If the expectant mother is expecting multiples the levels will be much higher and if there are no doubling of the levels it would suggest that there is something wrong with the pregnancy. The possibilities will include either a blighted ovum which will expel itself via a miscarriage or an ectopic pregnancy. A number of tests are used to measure the beta HCG levels in the blood including RIA (radioimmunoassay) , CLIA (chemiluminescent assay) and DELFIA ( fluorescent immunoassay) testing. The tests are so sensitive that positive levels (more than 10 mIU/ml) in the blood might be detectable as soon as teo days after a missed period.
In days gone by the only way to detect the presence of hCG was through urine tests in pregnancy test kits. Today there are some urine pregnancy kits that are very sensitive and can be used to detect a pregnancy as early as 1 to 2 days after missing a period as long as the blood hCG level is about 50 to 100 mIU/ml. The main benefits of urine pregnancy test kits are that they are inexpensive and that the tests can be carried out at home. To ensure that the results are accurate the instructions must be carefully followed. Simple things like urinary tract infections, failure to follow instructions and urine that is diluted can compromise the results.
Blood tests on the other hand are advantageous in that they will measure the actual beta hCG levels in the blood. This is something that can prove to be extremely helpful in detecting and managing any problems that might occur. Most physicians will order a test as early as 16 days into the pregnancy and one will be required 2-3 days after the first test. The levels should double every 2-3 days as the embryo continues to develop. This doubling is an indication that the pregnancy is progressing normally and the opposite is true if there is no increase in the beta hCG levels.
You might experience problems with hCG testing if you were given HCG (human chorionic gonadotropin) injections to induce ovulation. This exogenous HCG is usually excreted within 10 days but it might linger on. It is for this reason that if the results show low beta hCG levels the test would be repeated just to confirm that the levels are increasing. If you are given false positive result due to the hCG injection the levels will decline if you’re not but if you are it will increase.
Although hCG testing has proven to be helpful it’s major drawback is that it confirms pregnancy but it fails to provide details on the location of the pregnancy which may be tubal or ectopic.