Basic Information
Generic name: Human chorionic gonadotropin test strip
Advantages: fast, convenient, sensitive, high specificity
Function: It is convenient for women to detect whether they are pregnant
Product name: Early pregnancy (HCG) test strip
Test paper definition
The HCG colloidal gold detection kit adopts the double-antibody sandwich one-step method, and uses colloidal gold as an indicator to detect the concentration of HCG in urine to diagnose whether a woman is pregnant. Test strips are reliable indicators to assist clinical determination of pregnancy.
common name
Human chorionic gonadotropin (HCG) test paper (colloidal gold immunochromatography)
product name
Early pregnancy (HCG) test paper (colloidal gold immunochromatography)
Test paper principle
How to use early pregnancy test strips correctly? First of all, let's understand the principle of early pregnancy test strips:
Human chorionic gonadotropin (HCG) is a glycoprotein hormone produced by the placenta in pregnant women and is abundant in the urine of pregnant women. In the urine of non-pregnant women almost no HCG. The early pregnancy test strip adopts double-antibody sandwich one-step technology, and uses colloidal gold as an indicator to detect the concentration of HCG in urine to confirm whether a woman is pregnant.
Detection time
If the menstrual cycle exceeds three days, the early pregnancy test strip can be used to detect whether you are pregnant. Generally, it is more accurate one week after the menstrual cycle, when the HCG value increases significantly.
how to use?
Use a disposable clean container to collect fresh urine samples at any time, preferably in the morning.
◆ Operation steps
The instructions for use must be read completely before testing, and the reagents and urine samples should be returned to room temperature (20°C-30°C) before use.
1. take out the reagent strip from the original aluminum foil bag and use it as soon as possible within 1 hour.
2. Insert the reagent strip into the urine sample in the direction of the arrow. Note: The urine level should not exceed the marking line of the reagent strip.
3. After at least 5 seconds, take it out and place it on a clean and flat table to observe the results.
4. Wait for the appearance of the purple-red strip, and the test result should be read in 3 minutes. Invalid after 10 minutes.
◆ Result judgment
Positive (+): Two purple-red bands appear. One is in the test area (T) and the other is in the quality control area (C). Indicates pregnancy.
Negative (-): only a purple-red band appeared in the quality control area (C), and no purple-red band appeared in the test area (T). Indicates not pregnant.
Invalid: There is no purple band in the quality control area (C), indicating an incorrect operation process or the reagent strip has been deteriorated and damaged.
Note: The color bands of the quality control line and the test line of the reagent strip may show shades of color due to the amount of hCG in the urine, and the results are judged according to the above standards.
Testing method
1. Tear along the incision of the aluminum foil bag, and take out the test paper for testing.
2. Strip type: Immerse the end of the test paper with the arrow mark in the container containing the urine sample to be tested (the urine sample is not allowed to exceed the MAX line), and then take it out and lay it flat after about 3 seconds.
Cassette: Use a pipette to draw 0.2mL (3-4 drops) of the urine sample to be tested into the sample adding area.
Pen type: remove the cap, let the urine drip directly on the sample adding area when urinating, and maintain the urine collection time for 3 seconds (please note: the urine should not exceed the arrow, so as not to wet the test area and affect the detection result).
3. Observe the test results in the test area: Observe the test results within 5-10 minutes. Color development within 40 seconds is a strong positive.
Notice
1. There is no color band in the control line and the test line, indicating that the detection error should be tried again; when the HCG concentration is very high, the test line is very obvious, and the control line may become very weak, which is a normal result;
2. Conditional laboratories should use reference substances for simultaneous determination;
3. If the tested person still suspects the possibility of conception, and the urine test is negative, the morning urine can be collected again after 48 to 72 hours for re-measurement, and blood is drawn for HCG measurement if necessary;
4. Patients with uterine tumor, hydatidiform mole or menopause may have positive results due to high HCG content in urine.
The gynecological expert of Changsha Anzhen Maternity Hospital suggested that although the market claims that the accuracy rate of early pregnancy test strips has reached 99%, due to differences in the methods of use, the accuracy rate of general test results can only reach 50-75%. The results obtained by the laboratory test are indeed much more accurate than the results obtained by self-testing at home.
accuracy rate
Early pregnancy test strips test effect How to improve the accuracy of early pregnancy test strips? once a woman is pregnant, a pregnancy test strip can quickly detect a specific hormone in her urine-human chorionic gonadotropin to determine whether she is pregnant or not. this kind of test has the advantages of rapidity, convenience, sensitivity and high specificity, but it must not be taken lightly, because when using early pregnancy test strips for self-testing, if you do not pay attention to some unexpected situations, there may be false negatives or false positives.
So, how to improve the accuracy of early pregnancy test strips?
1. Pay attention to the production date on the box and do not use expired pregnancy test strips.
2. Read the manual carefully before doing the self-test, and then follow the instructions carefully.
3. Doing early pregnancy self-test at night will affect the accuracy more or less, while using morning urine will give more accurate results.
4. many early pregnancy test strips indicate that women can do early pregnancy self-tests after 1-2 days of missing their normal menstrual period. If the self-test result is negative, and there is still no menstrual period after one week, you should do another self-test.
5. If the pregnancy is just beginning, or there is an ectopic pregnancy such as an ectopic pregnancy, the urine to be tested needs to stand for more than 3 minutes (usually only 1 minute), and carefully identify whether there is a weak positive, that is, the color of the detection area is lighter than that of the control. area color, or only faintly.
6. Pay attention to the positive results of the self-test caused by non-pregnancy factors, such as blood in the urine, endometrial hyperplasia, ovarian tumor, recent pregnancy, expired abortion or incomplete abortion, etc.
7. Avoid urine dilution. If you drink too much water to dilute your urine, false-negative results may result.
8. Doing the test in the morning and evening may have a certain effect on the results. Morning urine generally has the highest HCG value, so many instructions recommend testing when you get up in the morning, but this is not absolute.
9. Pay attention to the length of the urine immersion test strip when testing. Occasionally the length of the urine immersion test strip is too long, which can make the test results difficult to judge
10. If you have been pregnant, you can judge whether you are pregnant or not based on the test results. Because HCG can remain positive for a longer period of time after termination of pregnancy (after childbirth, spontaneous abortion and induced abortion).
It should be reminded that the use of early pregnancy test strips for pregnancy self-test can only be used as a preliminary test, and must not be used as the final test result. It is the most reliable and reassuring to go to the hospital for a comprehensive and specific inspection.
Cause of misdetection
1. Time of detection. HCG generally does not appear in the urine until a few days after the fertilized egg implants, and it takes a certain amount to be detected. Therefore, for women with normal menstruation, it is possible to detect HCG in urine after menstruation is delayed. Women with long menstrual cycles or abnormal ovulation may not be detected until 40-44 days after menstruation.
2. Urine dilution. If you drink too much water to dilute your urine, false-negative results may result.
3. Doing the test in the morning and evening may have a certain impact on the results. Morning urine generally has the highest HCG value, so many instructions recommend testing when you get up in the morning, but this is not absolute.
4. Pay attention to the length of the urine immersion test strip when testing. Occasionally the length of the urine immersion test strip can make the test results difficult to judge.
5. Do not judge pregnancy based on the test results if you have been pregnant recently. Because HCG can remain positive for a longer period of time after termination of pregnancy (after childbirth, spontaneous abortion and induced abortion).
6. Some diseases and drugs may cause false positive results. Some tumor cells, such as hydatidiform mole, choriocarcinoma, bronchial carcinoma and renal carcinoma, can also secrete HCG.
7. Do not use expired test strips. Because chemical reagents lose their effectiveness over time, pay attention to the production date when purchasing.
8. Do not use wet test strips.
9. To get the correct result, it is best to do the early pregnancy test when the menstruation is delayed for two weeks. If the test comes back negative and your period is still coming after 1 week, you should do it again. It is inaccurate in the case of a recent pregnancy, because HCG can remain positive for a prolonged period of time after termination of pregnancy (postpartum, spontaneous abortion, and induced abortion). Some diseases and medications can cause false positive test results, such as blood in the urine, or taking some fertility drugs. Some tumor cells such as hydatidiform mole, choriocarcinoma, bronchial carcinoma and renal carcinoma can also promote the secretion of HCG in the body.
If your self-test is negative and your period is still coming after 1 week, you should do another self-test. If it's not positive, it's best to see a doctor. Trust your body. If you have various symptoms of pregnancy, no matter what the self-test results are, you should think that the principle of early pregnancy test strips is only a preliminary test, and there will be errors in using early pregnancy test strips. The best way is to go to the hospital for HCG blood test, HCG urine test and B-ultrasound. If you are not ready for the arrival of your baby, it is necessary to detect the early signs of pregnancy as soon as possible to determine whether you are pregnant or not.
Self-test results
Many women are accustomed to using early pregnancy test strips to test whether they are pregnant, and this method is usually used in hospitals to test. Pregnancy test strips are easy and fast to use, but will it give you the wrong message?
In fact, although the early pregnancy test paper claims to have a 99% accuracy rate, you must not put too much faith in your self-test results. According to expert statistics, the correct test rate of early pregnancy test strips varies widely, ranging from 50% to 98%.
Why is there such a big difference? Experts in gynecology point out that women do pregnancy self-tests at home without any outside guidance. Generally, the test results can only achieve an accuracy rate of 50% to 75%. If this test is done in the laboratory in front of a doctor, the doctor can ensure that the test strip is working properly, and the woman can use the test strip correctly according to the instructions without compromise, and the test accuracy rate may be close to 100%.
The manufacturer of the early pregnancy test strips and ovulation self-test mirror declares: "In the laboratory, the accuracy of today's early pregnancy test strips has been confirmed to be as high as 99%. However, when women use early pregnancy test strips, it is important to follow the instructions meticulously to ensure that The test results are correct and reliable." However, in practice, following the instructions correctly is not an easy task.
The description of some early pregnancy test strips reads: "Urinate at one end of the self-test card, so that the absorbing tip is facing down, and the display window should not face the body, so as not to splash urine on it." There are also early pregnancy test strips that guide users in this way" Hold the urine burette and drop 3 drops of urine down 3 cm above the urine dish at the bottom of the test strip." If you read the details of these instructions carefully several times and think carefully, there may be no problem. . However, for a woman who is nervous and panicked because she is afraid of pregnancy, because she cannot follow the instructions calmly and patiently, mistakes are inevitable. Moreover, the test results are also very confusing, whether it is the color response or the line response, it is not easy to explain.
If the pregnancy self-test is done at night, the accuracy rate will also be more or less affected. Because morning urine generally has the highest HCG value. Many early pregnancy tests do not state the best time of day to take the test. Generally, the most accurate results are obtained with the first urine excretion in the morning. Although a positive result is not as misdiagnosed as a negative result, there are a number of non-pregnant factors that can lead to a positive test result: blood in the urine, previous pregnancy (all possible after a miscarriage, abortion, or 8 weeks after giving birth) found HCG hormone), ovarian tumors and other diseases, or take some fertility drugs.
Other related
If the early pregnancy test strip is negative, it means that you are not pregnant, if it is positive, it means you are pregnant. If the early pregnancy test strip is weakly positive, it means that you may be pregnant, but the conditions are not very mature, so the test results are not very clear, you must go to the hospital Do formal inspections.
In order to make the early pregnancy test strips in the early pregnancy test strips test results always weakly positive and accurate, pay attention to the following aspects when using them:
Method 1 to prevent inaccurate results from weakly positive early pregnancy test strips: If the pregnancy has just begun, or there is a possibility of ectopic pregnancy, the samples whose HCG levels are generally low in the body should be left standing for more than 3 minutes, and must be carefully identified on the early pregnancy test strips. Is there a weak positive? The color band in the D?D detection area only appears faintly.
Method 2 to prevent inaccurate early pregnancy test strips that have always been weakly positive: If the early pregnancy test strips are stored for too long (more than 1 year) or the test strips are improperly stored (such as damp), and they are not kept at normal room temperature, they may fail. False negative test results occurred.
Three ways to prevent inaccurate early pregnancy test strips with weakly positive results: After 3 months of pregnancy, HCG levels drop, and early pregnancy test strips sometimes appear negative or weakly positive; a positive result does not mean 100% pregnancy.
Method 4 to prevent inaccurate results from weakly positive early pregnancy test strips: Weakly positive early pregnancy test strips, women of childbearing age who have menopause or suspect pregnancy, do not rely solely on a self-test on early pregnancy test strips to determine whether they are pregnant. To be on the safe side, you can test again after 3 days. Of course, the most reliable thing is to go to the hospital for a comprehensive examination in time, especially for those with weak positives, so that measures can be taken as soon as possible.
Five ways to prevent inaccurate early pregnancy test strips that have been weakly positive: Some tumor cells, such as moles, choriocarcinoma, bronchial cancer and kidney cancer, can also secrete HCG. We have also encountered patients with endometrial hyperplasia who tested positive for HCG.
Precautions
1. This product is only used for one-time in vitro diagnosis;
2. Open the package when it is determined to be used;
3. Use within the validity period;
4. If the early pregnancy test strip is stored for too long (more than 1 year), or the early pregnancy test strip is damp, and it is not kept at normal room temperature (should not be cold), it may fail, and the test result will be false negative;
5. If the pregnancy has just started, or there is a possibility of ectopic pregnancy (ectopic pregnancy), the samples whose HCG levels are generally low in the body need to stand for more than 3 minutes (usually only 1 minute), and must carefully identify whether there is a weak positive- - the detection zone color band appears only faintly;
6. After 3 months of pregnancy, HCG levels drop, and urine tests sometimes appear negative or weakly positive;
7. In extreme cases, such as hydatidiform mole, choriocarcinoma, and the level of HCG in the body will be too high, but the urine test will not show positive;
8. A positive result does not mean 100% pregnancy. Because some tumor cells such as hydatidiform mole, choriocarcinoma, bronchial carcinoma and renal carcinoma can also secrete HCG. Patients with endometrial hyperplasia may also have a positive HCG test;
9. When the HCG concentration exceeds 50,000 mIU/mL (usually at 2-3 months of pregnancy), a hook effect may occur (that is, the result may be negative), and it should be diluted before testing;
10. Patients with uterine tumors, moles, habitual abortion, threatened abortion, ectopic pregnancy or menopause may have positive results, and it is recommended that doctors make further diagnosis.
Test paper function
Human chorionic gonadotropin (HCG) is a glycoprotein hormone produced by the placenta during pregnancy. Taienkang early pregnancy test strips can quickly and reliably detect the presence of HCG in the urine of pregnant women and determine whether they are pregnant.
