Pregnancy tests can be performed both in blood or in urine.The main principle of both tests are, detecting hbHCG (Human Beta Chorionic Gonadothropine) hormone, which shows up in the blood of pregnant women, after the fertilized egg is planted on the uterus wall.
Urine pregnancy test: bhCG hormone is detected in the blood of pregnant woman as early as 6-10 days after the implantation of the fertilized egg but its presence in urine needs a longer time because bHCG reaches the bladder as the blood is filtered through the kidneys. This period will probably be approximately 10-12 days depending on the sensitiviy of the test material. To avoid false negative results, the tst should be repeated in 1-2 weeks after the expected menstrual bleeding.
Blood Pregnancy Test: The hormone can be detected in the blood 6-10 days after the implantation of the fertilized egg .This will be the ovulatuary phase of the menstrual cycle.
Today, In Vitro Fertilization techniques are increasing pregnancy rates and the pregnancy tests should be done on the day which is reccomended by the doctor. This is usually on 7-10 days after the transfer, but the test should be repeated in 2-7 days because bHCG is expected to increase by 2 folds each 72 hours in healthy pregnancies.
As the pregnancy is confirmed the bHCG hormone starts tor ise to its peak until the end of the first trimester and drops to lowest levels towards the end of the pregnancy.
BLOOD bHCG LEVELS AT THE PROGRESSING WEEKS OF THE PREGNANCY
IU/L | ||
3 rd week | 60-70 | |
4 th week | 10-750 | |
5th week | 200-7100 | |
6 th week | 160-32000 | |
7 th week | 3700-160000 | |
8 th week | 32000-150000 | 1stTRIMESTER |
9 th week | 64000-150000 | |
10 th week | 47000-190000 | |
12 th week | 28000-210000 | |
14 th week | 14000-63000 | |
15 th week | 12000-71000 | |
16 th week | 9000-56000 | |
16-29 weeks | 1400-53000 | 2ndTRIMESTER |
29-41 weeks | 940-60000 | 3rdTRIMESTER |
Sample: Arm vein blood. Nonfasting
Working day: Everyday
Result Time: 2 hours