Modern women are offered a huge selection of a wide variety of pregnancy tests, different modifications, designs, with different sensitivity. But I want to get the most accurate test system. Which tests are considered the most accurate, and how to get reliable results, this article will tell.
Operating principle
The pregnancy test is only outwardly different and is applied in different ways taking into account the design. The principle of operation of all test systems is exactly the same. It is based on the determination in the urine of a special substance characteristic of women "in position" - chorionic gonadotropin or simply hCG.
The test system has two working zones: one for control, the other for testing. In the control zone, a strip appears whenever the device comes into contact with liquid. This bar indicates that the test system is functional and can be used. A chemical reagent sensitive to hCG molecules is applied in the test zone, and if the level of this hormone in urine exceeds the threshold of the system's sensitivity, the reagent signals this by being colored red, blue or another color, showing "+".
Everyone has small amounts of the hCG hormone - in non-pregnant women of all ages, as well as in men. Its content is low - from 0 to 5 mU / ml.
But when pregnancy occurs, the concentration of the hormone reaches hundreds of thousands of units per milliliter, although not immediately.
About a week after conception, the embryo is implanted. The fertilized egg, which has descended into the uterus, begins a new period of its life - intrauterine. The baby will stay there until the very moment of his birth.
On the 6-9th day after fertilization, the embryo attaches to the endometrium (the inner wall of the uterus) and is retained thanks to the chorionic villi, they are connected during implantation with the blood vessels of the mother's body. The child begins to receive nutrients, oxygen and vitamins from the mother's blood, and hCG, produced by the chorionic villi, begins to enter the woman's blood.
Every two days, the level of the hormone in the blood increases 2 times, but if the pregnancy is multiple, then the growth depends on the number of fetuses (with twins - 4 times, with triplets - 6 times). After an increase in blood levels, there is an increase in the amount of chorionic gonadotropic hormone in the urine. Therefore, by the first day of the delay, the level of the hormone in the urine reaches values at which the reagent of almost any test begins to catch it.
Before the delay, the level of the hormone is low, and only ultrasensitive tests with a high sensitivity threshold can detect it.
Types of test systems
Considering how many systems are available for testing, the question of which test is more accurate does not seem strange. Don't assume that price determines performance. In the case of these products, this rule does not work. And sometimes the cheapest test is much more accurate than the expensive... Each type has its own disadvantages and advantages.
Stripes
Strip strips are the most popular and common type of test system used by women to determine pregnancy at home. This is a very simple device - a paper strip with two working zones. You need to collect urine, lower the strip to the level marked with the MAX designation, hold for 15-20 seconds and get it out. The result is evaluated after 5-10 minutes.
The use of such systems usually does not raise any questions - everything is simple and clear... The advantages include low cost of strips.
There are, of course, more expensive imported models, there are cheap domestic counterparts, but both work according to the same principle.
There are standard sensitivity tests - 20-30 mIU / ml... They show pregnancy with and after the onset of delay. There are more highly sensitive strip versions with a sensitivity from 5-10 mIU / ml to 15-20 mIU / ml.
The disadvantage can be considered the existing probability of obtaining false results. Such tests, according to statistics, give an unreliable result in about 5% of cases. On the other hand, the cost of strip strips is low, and it is quite possible to repeat the test to be sure of the result obtained earlier.
According to reviews, the most accurate results are given by strips Frautest, Evitest, Mom-Test, and I Was Born and Know-Now.
Tablet (cassette)
These test systems differ in modification. The kit includes a pipette that you need to apply urine into the test window. After a while, your result appears in the second window. A big and indisputable plus is the design. The plastic housing protects the working test area more securely, which increases the likelihood of more accurate results.
The disadvantages include the cost, which is higher than that of strips, as well as inconvenience in use.... It cannot be used outside the home, your own toilet room, since it requires preliminary collection of urine in a clean container, relative dexterity when instilling urine into the diagnostic window. If a woman is worried, her hands are trembling, it is highly likely that she will not immediately get where she should be.
But in general, such test systems are considered highly accurate, there are models with high sensitivity (from 10 units per milliliter), which suggests that the test shows pregnancy before the delay, of course, provided that the implantation took place within an average period (one week after conception) ... If the attachment of the embryo is delayed, then in the early stages before the delay, neither tablet nor other tests will show a positive result.
The most accurate tablet models among Russian women are the Evitest and Frautest test systems.
Inkjet
Jet-type systems are considered to be ultra-precise today. They are easy to use - the device only needs to be brought under the stream of urine by the working area and after a few minutes evaluate the result. They have a convenient body with a practical holder, there is no need to collect urine in advance, and therefore a woman can use the test both at home, in her own bathroom, and in the toilet at work, at school, wherever it is convenient for her.
Inkjet tests are disposable and reusable. Reusable are mainly represented by the digital segment, which will be discussed below. The accuracy of the result in ultrasensitive inkjet models (with a threshold of 5 to 20 units) a couple of days before the delay in menstruation allows you to get fairly reliable results.
The downside is the cost. Inkjet models are quite expensive. The most accurate, according to women's reviews, include Frautest, Evitest, Clearblue, Mom-Test.
Electronic
Digital tests are rightfully renowned as the most accurate systems for home diagnostics of "interesting position", and often they allow you to see the long-awaited positive result even before the next menstrual period is delayed. Digital electronic devices are designed for reusable use; they come with up to 20 replaceable disposable cartridges (1 cartridge for 1 analysis).
Some models have an additional function of determining the gestational age in weeks, but here the tests are often mistaken, since the program analyzes the hormone content that is statistically inherent in certain periods, and in practice, the level of the hCG hormone during pregnancy is a very individual matter.
The cost of such systems is the highest - from 350 to 600 rubles. The disadvantages of women include possible software failures. - for example, if the result is negative, the test shows the period in weeks.
Reusable electronic devices allow testing in any way available to a woman - by jet or with preliminary collection of urine, whoever likes what.
What affects the bottom line?
Since the principle of operation of a pregnancy test is similar to the principle of operation of a conventional litmus test, it is obvious that there are external and internal factors, depending on the woman and independent, which can affect the receipt of a particular result.
It should be noted that manufacturers of test systems for self-diagnosis of pregnancy indicate that the accuracy of their products exceeds 99%. This is not worth believing. Such an accuracy in a blood test for the content of chorionic gonadotropin, and this is by far the most reliable way to determine pregnancy in the early stages. Home tests, according to experts in the field of reproductive health, do not "pull" even by 97%. But for home diagnostics, this is quite a decent indicator.
If you want to get the most accurate result, try to adhere to a few important rules.
Timing
There is no reason to do the test 2 or 3 days after conception. During the first week after fertilization, the level of human chorionic gonadotropin in pregnant and non-pregnant women is at the same values and does not differ in any way. Therefore, remember that after ovulation, it is worth counting about 7-8 days, then wait another 2-3 days (for the first rise in the hCG level after implantation), and only then can one try to do an ultrasensitive test with a threshold of 5-10 mIU / ml.
But it should also be borne in mind that the tempting high accuracy declared on the box by the manufacturer is not only an advertising move, but also the expectation that a woman will start doing tests from the first day of her period delay.
Before the delay, no one guarantees anything at all. According to some reports, the most accurate (digital inkjet models) 5 days before the delay show pregnancy with a probability of only 50%. But already in 2 days the accuracy rises to 90% and by the beginning of the delay it approaches what was declared by the manufacturer. In this way, when trying to find out about pregnancy with a high-precision test 3-4 days before the start of the delay, it should be remembered that the accuracy of the result cannot be high.
And also recent studies have shown that after 6-8 obstetric weeks of pregnancy, the accuracy of the tests begins to decrease, since not only full-fledged hCG molecules are present in the urine with high hCG, but destroyed, and it is they who can show the absence of pregnancy with its already proven presence (5% cases of erroneous tests with a delay of 2-3 weeks are associated with this reason).
Correctness
No matter how much women want to have a very fast and very accurate way to find out whether a pregnancy has come or not, there is no need to rush - read the instructions carefully. Every third wrong test is a consequence of wrong actions on the part of the lady. Either the strip was overexposed in the urine, immersing it deeper than the marked line, or the result after 5 minutes was not satisfactory, and the woman waited another hour.
In these cases, a gray second strip may appear on the test, which ladies mistake for pregnancy, but in reality it is just a layer on which a chemical reagent was applied, and nothing more. After getting wet and dry, it may appear just like this.
Immerse the test to the mark indicated as maximum, hold strictly as much as the manufacturer recommends, evaluate the result after a certain period, no later than - this will be the key to improving accuracy.
If you are diagnosing before your period is missed, it is best to collect your morning urine sample. It is the most concentrated and dense in terms of the content of components, and it will be more likely to determine still small amounts of chorionic gonadotropic hormone. After a delay, especially if several days have passed, highly sensitive tests can be done at any time of the day, and systems with an average sensitivity (25-30 units) should be done in the same way in the morning on the first portion of urine after waking up.
If you conduct the test in the afternoon or in the evening, remember that before testing for 3-4 hours you need to refrain from drinking liquids, from foods that contain a large amount of it.
Other reasons
The level of hCG, fortunately, rises for no good reason, in the body rarely. Therefore, the only reasons that can affect the accuracy of your testing is the presence in the body of a hormone that was taken as part of fertility treatment. With IVF, when ovulation is stimulated, a single injection of hCG is given to ripen oocytes, and the level of the hormone in the blood remains elevated for up to two weeks. Therefore, after such treatment, do not rush to do tests, in general, there is a high probability of getting a positive result in the absence of pregnancy. It is better to take a blood test for hCG 2-3 times, and this will allow you to accurately judge pregnancy in dynamics.
If there was no such treatment, then high hCG outside pregnancy may be in the presence of malignant tumors, they produce hormones.
If a woman suspects that she could become pregnant while taking birth control pills (she forgot to take one or more pills on schedule), then you can use the test, because In principle, oral contraceptives do not contain hCG. Therefore, this will not affect the result.
A hormonal disruption that could have occurred is unlikely to "trick" sensitive test systems. If the failure is caused by an ovarian cyst or other cause, then there is an imbalance between progesterone and estrogen. If there are no neoplasms, then hCG will be negative.
Be sure to check that the test has a valid expiration date.
For information on how to do a pregnancy test, see the next video.
