السلام عليكم
اخواني الكرام
هذا موضوع بسيط يتحدث عن اختبار الحمل
اخواني الكرام
هذا موضوع بسيط يتحدث عن اختبار الحمل
hCG (Pregnancy test )
Also known as: Pregnancy test, Qualitatitve hCG, Quantitative hCG, Beta hCG, Total hCG, Total beta hCG
Formal name: Human chorionic gonadotropin
Why get tested?
To confirm and monitor pregnancy or to help diagnose and monitor trophoblastic disease or germ cell tumors
When to get tested?
As early as 10 days after a missed menstrual period (some methods can detect hCG even earlier, at one week after conception) or if a doctor thinks that your symptoms suggest ectopic pregnancy, trophoblastic disease, or germ cell tumors
Sample required?
A urine sample collected first thing in the morning or a blood sample drawn from a vein in the arm
What is being tested?
hCG is a protein produced in the placenta of a pregnant woman. A pregnancy test is a specific blood or urine test that can detect hCG and confirm pregnancy. This hormone can be detected 10 days after a missed menstrual period, the time period when the fertilized egg is implanted in the woman’s uterus. With some methods, hCG can be detected even earlier, at one week after conception.
During the early weeks of pregnancy, hCG is important in maintaining function of the corpus luteum . Production of hCG increases steadily during the first trimester (8–10 weeks), peaking around the 10th week after the last menstrual cycle. Levels then fall slowly during the remainder of the pregnancy. hCG is no longer detectable within a few weeks after delivery. hCG is also produced by some germ cell tumors and increased levels are seen in trophoblastic disease.
How is the sample collected for testing?
hCG is commonly detected in urine. The preferred specimen is a random urine sample collected first thing in the morning. hCG can also be measured in blood drawn from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed. However, do not drink large amounts of fluid before collecting a urine sample for a pregnancy test. This is because overly dilute urine may result in a false negative.
How is it used?
Qualitative hCG testing is routinely used to confirm pregnancy. Quantitative hCG testing (also frequently called beta hCG), measures the actual amount of hCG present in the blood. It may be ordered to help diagnose an ectopic pregnancy, to help diagnose and monitor a pregnancy that may be failing, and or to monitor a woman after a miscarriage. In addition, a quantitative hCG test may be ordered to diagnose trophoblastic disease or germ cell tumors of the testes or ovary. It may be ordered at regular intervals to monitor the effectiveness of treatment for these conditions and to detect tumor recurrence.
When is it ordered?
A qualitative urine or blood hCG test is ordered as early as 10 days after a missed menstrual period if a woman wishes to confirm whether or not she is pregnant (some methods can detect hCG even earlier, at one week after conception). In certain patients, several quantitative blood hCG tests over several days may be ordered to rule out an ectopic pregnancy or to monitor a woman after a miscarriage. A doctor will also order a quantitative hCG test when she suspects trophoblastic disease or the presence of germ cell tumors.
What does the test result mean?
In non-pregnant women, hCG levels are normally undetectable. During early pregnancy, the hCG level in the blood doubles every two to three days. Ectopic pregnancies usually have a longer doubling time. Those with failing pregnancies will also frequently have a longer doubling time or may even show falling hCG concentrations. hCG concentrations will drop rapidly following a miscarriage. If hCG does not fall to undetectable levels, it may indicate remaining hCG-producing tissue that will need to be removed.
hCG is also used to monitor treatment in patients with trophoblastic disease and to detect recurrent disease after treatment is complete. During therapy, a falling hCG level generally indicates that the cancer is responding to treatment, while rising levels may indicate that the cancer is not responding to therapy. Increased hCG levels after treatment may indicate a recurrence of disease.
Is there anything else I should know?
Tests performed too early in the pregnancy, before there is a significant hCG level, may give false-negative results, while blood or protein in the urine may cause false-positive results. Urine hCG tests may give a false negative result in very dilute urine. Patients should not drink large amounts of fluid before collecting a urine sample for a pregnancy test.
Certain drugs such as diuretics and promethazine (an antihistamine) may also cause false-negative urine results. Other drugs such as anti-convulsants, anti-parkinson drugs, hypnotics, and tranquilizers may cause false-positive results.
There are reports of false positive serum hCG results due to several different compounds (not drugs) that may interfere with the test. These include certain types of antibodies that may be present in some individuals and fragments of the hCG molecule. Generally, if results are questionable, they may be confirmed by testing with a different method.
1. How does the test that I do at home myself compare with the results of a test done in a lab?
Home pregnancy testing is very similar to qualitative urine hCG testing in the laboratory, but there are factors surrounding its use that are important to note.
• First, home tests come with very specific directions that must be followed explicitly. If you are using a home test, follow the directions extremely carefully.
• Second, home tests are sometimes done too soon after the missed menstrual cycle to result in a positive test; it takes 10 days after conception before the presence of hCG can be detected by the urine test. That is why a home test is sometimes negative when the test done by your doctor is positive—the doctor’s test is often done several days later when hCG levels have become detectable.
• All urine qualititative hCG tests should be done on a first morning urine sample, if possible. Urine becomes more dilute after ingestion of liquids (coffee, juice, water, etc.) and urine hCG concentrations may become too low to register as positive.
Generally, when used correctly, the home test should produce the same result as the urine hCG test done by your doctor. Qualitative blood testing for hCG may be more sensitive than urine hCG testing, so sometimes a blood test will indicate pregnancy when the urine test is negative. Quantitative hCG testing requires a blood sample and must be done in the laboratory.
2. What is an ectopic pregnancy?
An ectopic pregnancy is the condition when the fertilized ovum (blastocyst) implants somewhere other than in the uterus. This is a serious condition needing immediate treatment. Patients with ectopic pregnancies often have abdominal pain and uterine bleeding. Usually, abnormally low levels of hCG are produced in ectopic pregnancies with slower-than-normal rates of increase.
3. When is a blood hCG test ordered instead of a urine hCG?
The blood hCG test actually measures the amount of hCG in the blood; the urine hCG is used to detect the presence of hCG. Since hCG is not normally detected in the urine of a non-pregnant woman, the urine hCG is enough to confirm a pregnancy. Sometimes, it is important to know how much hCG is present to evaluate a suspected ectopic pregnancy or to monitor a woman following a miscarriage. In these circumstances, your doctor will run a blood hCG.
4. How many days after a miscarriage would it take for a urine pregnancy test to show a negative result?
Urine hCG disappears at about the same rate as serum hCG, which can take anywhere from 9 to 35 days, with a median of 19 days. However, the timeframe for when an hCG result will be negative is dependent on what the hCG level was at the time of the miscarriage. Frequently, miscarriages are monitored with quantitative blood hCG testing. If the levels of hCG do not fall to undetectable levels, some hCG-producing tissue may remain and have to be removed.
Also known as: Pregnancy test, Qualitatitve hCG, Quantitative hCG, Beta hCG, Total hCG, Total beta hCG
Formal name: Human chorionic gonadotropin
Why get tested?
To confirm and monitor pregnancy or to help diagnose and monitor trophoblastic disease or germ cell tumors
When to get tested?
As early as 10 days after a missed menstrual period (some methods can detect hCG even earlier, at one week after conception) or if a doctor thinks that your symptoms suggest ectopic pregnancy, trophoblastic disease, or germ cell tumors
Sample required?
A urine sample collected first thing in the morning or a blood sample drawn from a vein in the arm
What is being tested?
hCG is a protein produced in the placenta of a pregnant woman. A pregnancy test is a specific blood or urine test that can detect hCG and confirm pregnancy. This hormone can be detected 10 days after a missed menstrual period, the time period when the fertilized egg is implanted in the woman’s uterus. With some methods, hCG can be detected even earlier, at one week after conception.
During the early weeks of pregnancy, hCG is important in maintaining function of the corpus luteum . Production of hCG increases steadily during the first trimester (8–10 weeks), peaking around the 10th week after the last menstrual cycle. Levels then fall slowly during the remainder of the pregnancy. hCG is no longer detectable within a few weeks after delivery. hCG is also produced by some germ cell tumors and increased levels are seen in trophoblastic disease.
How is the sample collected for testing?
hCG is commonly detected in urine. The preferred specimen is a random urine sample collected first thing in the morning. hCG can also be measured in blood drawn from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed. However, do not drink large amounts of fluid before collecting a urine sample for a pregnancy test. This is because overly dilute urine may result in a false negative.
How is it used?
Qualitative hCG testing is routinely used to confirm pregnancy. Quantitative hCG testing (also frequently called beta hCG), measures the actual amount of hCG present in the blood. It may be ordered to help diagnose an ectopic pregnancy, to help diagnose and monitor a pregnancy that may be failing, and or to monitor a woman after a miscarriage. In addition, a quantitative hCG test may be ordered to diagnose trophoblastic disease or germ cell tumors of the testes or ovary. It may be ordered at regular intervals to monitor the effectiveness of treatment for these conditions and to detect tumor recurrence.
When is it ordered?
A qualitative urine or blood hCG test is ordered as early as 10 days after a missed menstrual period if a woman wishes to confirm whether or not she is pregnant (some methods can detect hCG even earlier, at one week after conception). In certain patients, several quantitative blood hCG tests over several days may be ordered to rule out an ectopic pregnancy or to monitor a woman after a miscarriage. A doctor will also order a quantitative hCG test when she suspects trophoblastic disease or the presence of germ cell tumors.
What does the test result mean?
In non-pregnant women, hCG levels are normally undetectable. During early pregnancy, the hCG level in the blood doubles every two to three days. Ectopic pregnancies usually have a longer doubling time. Those with failing pregnancies will also frequently have a longer doubling time or may even show falling hCG concentrations. hCG concentrations will drop rapidly following a miscarriage. If hCG does not fall to undetectable levels, it may indicate remaining hCG-producing tissue that will need to be removed.
hCG is also used to monitor treatment in patients with trophoblastic disease and to detect recurrent disease after treatment is complete. During therapy, a falling hCG level generally indicates that the cancer is responding to treatment, while rising levels may indicate that the cancer is not responding to therapy. Increased hCG levels after treatment may indicate a recurrence of disease.
Is there anything else I should know?
Tests performed too early in the pregnancy, before there is a significant hCG level, may give false-negative results, while blood or protein in the urine may cause false-positive results. Urine hCG tests may give a false negative result in very dilute urine. Patients should not drink large amounts of fluid before collecting a urine sample for a pregnancy test.
Certain drugs such as diuretics and promethazine (an antihistamine) may also cause false-negative urine results. Other drugs such as anti-convulsants, anti-parkinson drugs, hypnotics, and tranquilizers may cause false-positive results.
There are reports of false positive serum hCG results due to several different compounds (not drugs) that may interfere with the test. These include certain types of antibodies that may be present in some individuals and fragments of the hCG molecule. Generally, if results are questionable, they may be confirmed by testing with a different method.
1. How does the test that I do at home myself compare with the results of a test done in a lab?
Home pregnancy testing is very similar to qualitative urine hCG testing in the laboratory, but there are factors surrounding its use that are important to note.
• First, home tests come with very specific directions that must be followed explicitly. If you are using a home test, follow the directions extremely carefully.
• Second, home tests are sometimes done too soon after the missed menstrual cycle to result in a positive test; it takes 10 days after conception before the presence of hCG can be detected by the urine test. That is why a home test is sometimes negative when the test done by your doctor is positive—the doctor’s test is often done several days later when hCG levels have become detectable.
• All urine qualititative hCG tests should be done on a first morning urine sample, if possible. Urine becomes more dilute after ingestion of liquids (coffee, juice, water, etc.) and urine hCG concentrations may become too low to register as positive.
Generally, when used correctly, the home test should produce the same result as the urine hCG test done by your doctor. Qualitative blood testing for hCG may be more sensitive than urine hCG testing, so sometimes a blood test will indicate pregnancy when the urine test is negative. Quantitative hCG testing requires a blood sample and must be done in the laboratory.
2. What is an ectopic pregnancy?
An ectopic pregnancy is the condition when the fertilized ovum (blastocyst) implants somewhere other than in the uterus. This is a serious condition needing immediate treatment. Patients with ectopic pregnancies often have abdominal pain and uterine bleeding. Usually, abnormally low levels of hCG are produced in ectopic pregnancies with slower-than-normal rates of increase.
3. When is a blood hCG test ordered instead of a urine hCG?
The blood hCG test actually measures the amount of hCG in the blood; the urine hCG is used to detect the presence of hCG. Since hCG is not normally detected in the urine of a non-pregnant woman, the urine hCG is enough to confirm a pregnancy. Sometimes, it is important to know how much hCG is present to evaluate a suspected ectopic pregnancy or to monitor a woman following a miscarriage. In these circumstances, your doctor will run a blood hCG.
4. How many days after a miscarriage would it take for a urine pregnancy test to show a negative result?
Urine hCG disappears at about the same rate as serum hCG, which can take anywhere from 9 to 35 days, with a median of 19 days. However, the timeframe for when an hCG result will be negative is dependent on what the hCG level was at the time of the miscarriage. Frequently, miscarriages are monitored with quantitative blood hCG testing. If the levels of hCG do not fall to undetectable levels, some hCG-producing tissue may remain and have to be removed.
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