HCG TOTAL URINE QUALITATIVE-PREGNANCY
Also known as:
- Quantitative blood pregnancy test.
- hCG blood test.
- Serial beta-hCG test (β-hCG).
- Quantitative serum beta-HCG test.
- Pregnancy test.
What is The Human Chorionic Gonadotropin Test?
hCG is a hormone secreted in the initial stages of pregnancy by the trophoblasts of the fertilized ovum that supports the corpus luteum to secrete estrogen and progesterone. The human chorionic gonadotropin test determines hCG hormone levels in the blood during pregnancy. It is produced by the cells present in your placenta that nourish the egg after fertilization and connect to the uterine wall.
It is possible to detect hCG in a blood sample about ten days after conception. The hCG levels keep increasing two folds every 48 to 72 hours. It is usual for hCG levels to reach their peak around 7-10 weeks, then decrease and level off, remaining consistent for the rest of the pregnancy.
The hCG levels can be detected either in blood or urine to confirm the pregnancy. However, the urine test can only show whether the sample is positive or negative for hCG; hence, it is qualitative. On the other hand, the beta hCG is a quantitative test, which helps determine the exact amount of hCG present in your blood sample.
What is the Test Used For?
Your doctor may suggest an hCG test to confirm pregnancy at the initial prenatal visits after a positive at-home test or urine test. However, an hCG quantitative test is not necessary for routine pregnancies. Most practitioners prefer going for a transvaginal ultrasound for visible evidence that everything is smooth in your pregnancy.
A beta-hCG test is also used in complicated, high-risk pregnancies or miscarriages. In such circumstances, your doctor might advise you to repeat the test every two days to assess how rapidly hCG levels are rising.
Why and when do you need a beta-hCG test?
Other than pregnancy confirmation, your doctor may advise this test if you are undergoing fertility treatments right before your menstruation date to see if your efforts are bringing positive changes. Healthcare teams caring for those women who take hCG shots to increase their chances of getting pregnant need to accurately time a beta-hCG test to ensure that the medicine has entirely left the body and will not alter test results.
This test is also needed in some other cases such as:
Determining the age of a fetus
While a beta-hCG test cannot always tell you precisely about the gestational age, your results and the date of your last period can give your doctor a general idea, as hCG ranges change every week in the first trimester.
A beta hCG is also a part of the screening tests done between the second and third trimester of pregnancy to evaluate fetal health problem markers, including Down syndrome.
Outside of pregnancy, Beta hCG has been deemed a tumor marker, meaning it is a hormone excreted in some types of cancers. That's why doctors recommend an hCG blood test to diagnose and manage certain cancers. That includes lung cancer, breast cancer, and the cancer of the uterus.
What kind of sample is required for the test?
An hCG real quantitative test determines the hCG levels in the blood sample.
A healthcare professional or phlebotomist withdraws a blood sample in a few steps.
- A band will be tied around your upper arm to stop the blood flow.
- The phlebotomist will locate a vein and clean the area using an alcohol swab.
- The needle is then injected into the vein, and the blood will be collected.
- After the sample collection, the band will be removed from your arm.
You might experience a slight stinging sensation when the needle is injected, or you may feel nothing at all.
Do you need to prepare for the test?
No specific preparation is needed for the beta-hCG blood test.
Are there any risks to the test?
Risks involved in withdrawing a blood sample are usually minimal.
You may feel minor bruising at the site of the injection. It is suggested to apply pressure to the area to prevent bruising.
In rare cases, the following may occur:
- Swollen veins
What do the test results mean?
The chart below describes the reference ranges of hCG in pregnancy. However, these are basic guidelines because every pregnancy is different.
|Weeks ( since last period)||Reference ranges (if pregnant)|
In men and non-pregnant women, the normal hCG levels are less than 10 mIU/ml.
As mentioned above, elevated levels are seen with pregnancy and with HCG-secreting tumors. A rise in hCG levels above the reference range in patients with a history of an hCG-producing condition suggests repetitive disease.
In pregnancy, levels of hCG that are higher than usual may indicate:
- You miscalculated your pregnancy or last period date.
- An unusual mass forms inside the uterus after fertilization rather than a normal embryo in a molar pregnancy.
- Multiple pregnancies, when you are expecting twins or triplets.
Levels of hCG that are lower than usual could mean:
- A miscalculation of pregnancy dating
- Blighted ovum
- An ectopic pregnancy
Is the hCG blood test always correct?
No, the hCG blood test is not 100 percent precise every time.
You may get both false-negative results and false-positive results from an hCG test for pregnancy. Your doctor will advise you to repeat the test in case of any doubt.
False-negative test results:
A negative beta-hCG test means you are not pregnant. However, if the test is performed too early in pregnancy, the levels are not high enough to get detected. A false-negative test result shows that a woman isn't pregnant, when in fact, she is. It happens because hCG levels change rapidly during early pregnancy. Repeating the hCG blood tests within 48 to 72 hours is recommended to avoid getting false-negative results.
On the other hand, it is possible to detect hCG in some non-pregnant conditions, causing a false-positive hCG pregnancy test. A False-positive result shows you are pregnant when you are not. You may get a false-positive result if your body produces specific types of antibodies that have traces of the hCG molecule, or sometimes a lab error might give you false results.