Urine pregnancy test accuracy
1. What is the urine pregnancy test:
Usually, Urine pregnancy test accuracy are performed at home (instead of in the clinic). The home uses kits to measure HCG in the urine. ( HCG i.e. Human chorionic gonadotropin is a hormone produced in women during pregnancy. The hormone nourishes the egg after it has been fertilized by sperm cells. The presence of HCG in urine and also in the blood is essential to detect pregnancy).
However, the urine pregnancy test is qualitative as it detects only the presence (and conversely the absence) of HCG and not the level or quantity of the HCG hormone. When a woman becomes pregnant the body produces pregnancy hormone (HCG) which is detected in the urine to confirm pregnancy.
Most urine pregnancy tests are taken from the 1st day ( and onwards) of one’s missed period (menstrual period). Urine pregnancy tests taken earlier may not be accurate for confirming pregnancy. HCG can be detected in urine (also in blood) after implantation which occurs on average 9 days (6—12 days) after fertilization. (implantation is the early symptom of pregnancy which involves light bleeding. It is the process by which a fertilized ovum or egg implants into the urine wall to obtain oxygen and nutrients from the mother. Implantation may often be mistaken for a regular menstrual period).
2. How the urine pregnancy test is taken:
- Usually, urine pregnancy tests are taken at home by using a bottle or vessel to contain sample urine which needs to be left untouched (for 3—4 hours). If a white film forms on the surface, then pregnancy is confirmed. But if the urine remains clear and there is no change in urine, then no pregnancy symptom is found.
- It is wise to carry a test with a morning urine sample when it has the strongest concentration of HCG hormone.
- Urine pregnancy test can also be done (known as the toothpaste test) by placing a moderate amount of toothpaste in a cup and then adding a few drops of urine to it. If the urine changes color or begins to froth, then, the woman is probably pregnant. If there is no change in color, then there is no pregnancy.
- Bleach test, another urine pregnancy test at home, needs to collect the 1sr urine of the day. Some bleaching powder is added to the collected urine. If the urine starts fizzing and foaming, then there is a good chance of pregnancy to occur.
3. Comparative advantage and disadvantage of urine pregnancy test:
3.1) Urine pregnancy test (qualitative test) is easy, cost-effective and convenient as it can be performed at any time at home and there is no need to go to the clinic for performing the test. The result of a home pregnancy test for urine is given within a few hours (unlike quantitative test result for blood which is given within a day or two.)
3.2) The doctor usually recommends the urine pregnancy test (qualitative test ) as the 1st step before doing the quantitative test. Quantitative test for blood is recommended only after taking the urine pregnancy test.
3.3) Since the home urine pregnancy test is qualitative, it can simply tell ‘yes’ or ‘no’ about the presence of HCG hormone in the urine, but cannot quantify or estimate the level of HCG hormone. Also, the home pregnancy urine test cannot differentiate between healthy pregnancy (It implies a healthy mother during and after pregnancy as well as a healthy baby after birth with the least delivery complications) and unsustainable pregnancy (It implies disorder in the normal pregnancy procedure). On the other hand, the quantitative test estimates and quantifies the HCG level (present in the blood). The doctor performs the quantitative test by applying advanced medical procedures. As the blood test for pregnancy (performed in the clinic) is both qualitative and quantitative, hence the test is more important and useful for taking necessary precautionary measures about the healthy birth of the baby after pregnancy is confirmed.
3.4) The urine pregnancy test (at home) has the least botheration as compared to the quantitative pregnancy test for blood which needs to be performed in the clinic during the scheduled period under a doctor or pathologist who takes a blood sample by inserting a needle into the vein of the arm near the elbow.
3.5) The urine pregnancy test is simple unlike the quantitative test for blood which is more elaborate and hence considered more accurate.The quantitative pregnancy test result for blood contains detailed information which is quite helpful (for instance, the quantitative test results are well interpreted in the report. The pregnancy information is nicely and elaborately quantified. If the HCG level lies below 5 ml U/ ml, then no pregnancy occurs. If the HCG level exceeds 25 ml U/ml, then pregnancy is confirmed. And if the HCG level lies between the 2 extremes: 5 ml U/ml—25 ml U/ml, then the repetition of the test is advised)
4. Factors affecting the accuracy of urine pregnancy test:
4.1) For having the most accurate and reliable test result, the urine pregnancy test must be taken preferably one week after the missed period (when the HCG level is most likely to be detectable). In this connection it needs to be mentioned that the earlier (after the missed period) the urine pregnancy test is taken, the harder it is for the test to detect HCG.
4.2) Women's menstrual cycle can vary widely. So, if one conceives later in her cycle, the HCG level may not be enough at the time of the missed period. Consequently, a false-negative test result will appear. For attaining accuracy, it is therefore suggested to wait a few days, preferably, 7—10 days after ovulation (ovulation is the release of egg or ovum which may subsequently be fertilized by a sperm cell or dissolved during menstruation. The ovulation process is defined by a period of elevated hormones during the menstrual cycle)
4.3) The 1st-morning urine specimen is the most appropriate for the accurate urine test results and microscopic analysis.
4.4) If one is currently pregnant but, HCG is not identified to confirm pregnancy, then it is a case of abnormal HCG which implies miscarriage (it is the loss of a fetus before the 20th week of pregnancy period. The most common symptoms of miscarriage are vaginal bleeding that may vary from light to heavy, possibly with blood clots. Bleeding and cramps may persist if miscarriage is not complete. A completed miscarriage can be confirmed by an ultrasound. Some women may experience a miscarriage without knowing it.) or Ectopic pregnancy (It is a case of pregnancy with complications which occurs when the fertilized egg attaches somewhere outside the uterus. An untreated ectopic pregnancy may invite medical emergency )
4.5) During the 1970s the urine pregnancy test was first developed to look into the indicator (HCG level in the urine). For arriving at accurate urine pregnancy test result, one needs to carefully read and meticulously follow the instruction before taking the test
4.6) A little impatience can invite test errors and so, mistakes in taking the test may lead to false-negative (or false positive ) pregnancy test results.
4.7) Skipping certain steps in the urine pregnancy test can affect accuracy. For instance, it is essential to put urine under test for the recommended period.
4.8) If one drinks too much water (before a test), then it will dilute the concentration of HCG in urine which will adversely affect the accuracy in the urine pregnancy test result.
4.9) Certain medications containing HCG (for example, ‘personal’ and ‘pregnancy’) can adversely affect the accuracy of the test result.
5.1) ‘First Response’ pregnancy test is accepted as the best urine pregnancy test in terms of speed, sensitivity and the accuracy of the test result
5.2) To have the most accurate test to confirm pregnancy it is essential in addition to taking a blood test in the clinic by an efficient health care provider.
5.3) Apart from taking pregnancy test for urine (and additionally blood test) to detect HCG to confirm pregnancy, it is important also to look into the symptoms of pregnancy which include: tender swollen breast, fatigue, slight bleeding or cramping, nausea (with or without vomiting), food aversion or craving, headaches, constipation, and mood swings
5.4) It is possible to get pregnant even if she has no period at all. In such a condition with health complications, it is advised to immediately consult a physician.
5.5) A false negative pregnancy test result (even if one is, in fact, pregnant) is more likely to occur as compared to the cases with false positive pregnancy test result (even if one is not pregnant.)
5.6) A high HCG level may often indicate molar pregnancy (It is an abnormal pregnancy in which a non-viable fertilized egg implants in the uterus and ultimately fails. It is a kind of GTD i.e. Gestational trophoblastic disease which grows in a mass into the uterus. The abnormal tissue from the mole can continue to grow even after it is removed. And consequently, it can turn into cancer.), multiple pregnancy (It is a pregnancy condition wherein the pregnant mother delivers 2 or more offspring. Multiple births occur in case of most of the mammals with varying frequencies) and ovarian cyst or tumor (These are fluids in the ovary. The ovarian cysts are found common and usually form during ovulation. The cysts are usually harmless. Many women with ovarian cysts don’t have symptoms). Conversely, a low HCG level may indicate the wrong prediction of pregnancy and ectopic pregnancy.
5.7) The HCG hormone level usually goes on increasing with the progression of pregnancy.
For confirming the accurate pregnancy test results It is highly recommended by the medical professionals to take both the qualitative test (home pregnancy test for urine) followed by the quantitative test for blood in addition to examining the pregnancy signs and the symptoms as well as specific health complications if any.