QF-PCR in prenatal diagnosis is one of the techniques used to diagnose fetal abnormalities in many medical facilities. If in the past it had to wait until birth to detect birth defects, today the development of medicine, parents can fully know about fetal defects through prenatal screening tests.
What Is QF-PCR In Prenatal Diagnosis?
QF-PCR in prenatal diagnosis is a test technique used to diagnose abnormal signs of multiple chromosomes through molecular biology obtained from fetal amniotic cells.
Unlike other prenatal diagnoses, QF-PCR will adopt a completely different technique. This method will amplify DNA fragments to clone the gene and run tests for abnormalities.
This test will use fluorescent signals combined with quantitative methods via the ABI 3500 type electrophoresis machine to mark the DNA fragments that need to be amplified for testing.
QF-PCR Tests in Prenatal Diagnosis
Depending on the number of aneuploidy, there will be accurate assessments of the fetal abnormality. Some syndromes can be detected when using the QF-PCR test that as Down syndrome, Patau, Edwards, Klinefelter, Jacobs, Turner …
- Tests showed that aneuploid 21 chromosomes were diagnosed to cause Down syndrome in a newborn (trisomy 21).
- If aneuploidy number 13 will cause Patau's syndrome in the baby (trisomy 13)
- Trisomy 18, if aneuploid, leads to Edwards syndrome (trisomy 18).
- If the sex chromosome X, Y is aneuploidy, it will lead to the syndrome as Jacobs, Turner, and Klinefelter.
When to Get Tested QF-PCR
When the fetus is diagnosed with the above conditions, a QF-PCR test is required in prenatal diagnosis. From there to accurately conclude abnormal conditions in the fetus if any.
Usually, this test is ordered along with an autosomal test if the mother has one of the following factors:
- In case of pregnant women doing Double test or Triple test with results of a fetus at risk of birth defects, QF-PCR test is required.
- Ultrasound images of the fetus with abnormalities such as heart defects, gastrointestinal tract or crooked feet, handgrip, and a number of other abnormalities related to blurred back nape and nasal bone loss. These are abnormalities that can be detected with an ultrasound of the fetus at regular antenatal check-up timelines.
- If pregnant are over 35 years old, an additional QF-PCR test is required. Because this age when pregnant will have a very high rate of fetal malformations. Therefore, pregnant women over 35 years of age are often counseled to have QF-PCR testing in addition to regular routine tests.
- In the case of pregnant with a history of pregnancy or childbirth with genetic factors, it is also necessary to have a QF-PCR test in prenatal diagnosis to rule out the possibility that the fetus can have a genetic disease like previous cases that pregnant women had.
- If your family has a genetic disease, you should also have a QF-PCR test. In particular, if either parent or both are determined to have signs of an anomaly, the pregnant should carry out all prenatal diagnostic tests during pregnancy including QF-PCR.
In this case, when planning to become pregnant, the couple needs to see a doctor and consult a specialist to avoid defects in the fetus.
Procedure for QF-PCR in Prenatal Diagnosis
A variety of patient samples can be collected for the QF-PCR test. Usually, a pregnant will be tested through amniotic fluid. This is the most commonly used test. Alternatively, the test can be done through blood, vegetable thorns, or umbilical cord blood.
The QF-PCR procedure is conducted according to the following steps:
- When the fetus is 16-18 weeks old, an amniocentesis will be performed for QF-PCR. Amniocentesis will be indicated through ultrasound guidance. The technician will use a needle to poke the amniotic fluid. Through the abdominal wall will insert a needle to get amniotic fluid with a capacity of about 4ml to 6ml.
- The amniotic fluid sample will be sent to the laboratory for processing and analysis of the results. This is in the case of amniocentesis and laboratory diagnosis at the same facility. In cases where the specimens and the test sites are not located close together, it is necessary to store the amniotic fluid at a temperature of 4 ° C. In particular, during transport, it is necessary to ensure the specimen is kept refrigerated.
- After receiving the amniotic fluid sample, the test technicians will perform DNA extraction from the amniotic fluid.
- Through a thermostat, PCR reactions will be carried out in about 2.5 hours.
- After performing the reaction on the thermostat, it will be done on ABI 3500 to analyze the results of capillary electrophoresis.
Advantages and Disadvantages of The QF-PCR Assay Method
QF-PCR assay in prenatal diagnosis has limitations. It is this method that can only evaluate and determine aneuploidy of 5 chromosomes. The other chromosomes in the 46 chromosomes cannot diagnose all of them. Therefore, QF-PCR can only accurately diagnose the syndromes associated with Down, Klinefelter, or Patau, Edward, and Turner diseases.
In addition, for cases of chromosomal fragmentation with a very small size of less than 2Mb, this method will not be able to detect. These are limitations that the QF-PCR test has not improved.
However, this method has the advantage of being very quick to return results. Only about 2-3 days, pregnant can receive and read the results of QF-PCR to accurately diagnose the fetal abnormal condition if they have one of the 5 conditions mentioned above. In addition, using the QF-PCR method does not require incubation time, so testing is done more quickly and easily.
Another advantage that QF-PCR tests aim at is that when done, the test will not take too many amniotic cells. From there, will minimize the risks that can occur when the amniocentesis is tested.
Some Notes When Doing QF-PCR Test
- QF-PCR test is performed when specifically directed by your doctor and when the fetus is 16-18 weeks old. Because if the amniocentesis is too early or too late, the risk of miscarriage or fetal damage is very high. Therefore, the right time to appoint QF-PCR should be chosen.
- Pregnant undergoing QF-PCR should be consulted by a specialist. Because there are drawbacks that will directly affect the test results such as drugs or supplements that pregnant are taking. Therefore, pregnant need to provide full information related to their pregnancy to the doctor.
- After performing the QF-PCR test, pregnant need to rest completely for about 2 hours after the test. After about 2 weeks, you should pay attention to moving, gently walk so that the body can recover quickly and not affect the fetus.
- When doing the QF-PCR tests, pregnant need to pay attention to choose a reputable testing facility to avoid potential risks.
Testing with the QF-PCR technique in prenatal diagnosis requires modern machines and high-tech equipment. Therefore, if you want to perform this test method, you need to find reputable, good quality facilities with modern machines and equipment.
Diag is one of the leading addresses in the field of modern medical testing and diagnostics, giving fast and accurate results. With a team of doctors with many years of experience, high expertise will bring you the best service. For more information, please contact Diag 1900 1717 for conscientious advice and support.
Above is information on QF-PCR in prenatal diagnosis. Hope the above information will help you better understand this test method.
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