POC Testing
About Products of Conception (POC) testing
POC test is used to analyze fetal tissue from a miscarriage, to determine if the loss of a pregnancy is due to a chromosomal aneuploidy (the appearance of an extra or missing chromosome). POC is a medical term used to identify the tissue that develops as a result of pregnancy.
This test can provide you with important information regarding the possible causes of your miscarriage and help you to appropriately plan any future pregnancy.
Placental or fetal tissue remaining in the uterus after a miscarriage, planned abortion, preterm, or term delivery is called retention of conceptus (RPOC). A miscarriage with RPOC means it was an incomplete miscarriage rather than a complete miscarriage.
When is POC recommended?
POC is recommended for all women who have had a miscarriage but is essential for women who have had repeated, spontaneous miscarriages and those undergoing assisted reproduction treatments.
Sample collection and preparation
Your doctor will advise you on pre-test preparations, make sure to follow instructions closely.
Commonly, your doctor will look for tissue during a dilation and curettage (D&C) procedure. It is a routine surgical procedure performed following a miscarriage during the first trimester or to diagnose and/or treat conditions that affect the uterus such as abnormal bleeding. It is also performed using a spoon-shaped device called a curette which gently scrapes the uterine wall lining. Sometimes, an endometrial biopsy is performed where a small piece of fetal tissue from your uterus is removed.
The preferred specimen types for chromosomal analysis include placenta, umbilical cord, fetus skin or organ biopsy sample.
Cell culture: In order to establish cultures for chromosome analysis, tissues must be obtained as fresh as possible and without contamination. The tissue samples are carefully washed in sterile saline and are placed into cell culture media (nutrient solution required for growth) to increase the yield of the cells.
Symptoms of retained POC
Enlarged uterus
Fever
Uterine bleeding
Light or infrequent menstrual periods
Infection
Pelvic pain
Types of tests for diagnosis of POC
The following tests are used to diagnose RPOC:
Human chorionic gonadotropin (hCG) test
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This test is used to measure the amount of hCG hormone in blood which is produced by the placenta. RPOC may lead to high hCG levels after pregnancy or miscarriage if pieces of the placenta are still present in the uterus.
Endometrial biopsy
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In this procedure a small piece of tissue from uterus is removed and examined under a microscope. The presence of placental tissue cells or chorionic villi means that there is still placental tissue present in the uterus.
Imaging exams
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Imaging exams performed using transvaginal ultrasound checks for an enlarged or thickened uterine lining and tissue masses with an ultrasound probe inserted in the vagina.
- Chromosomal abnormalities associated with spontaneous abortions are diagnosed using
Chromosomal Analysis
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This is used to look at the chromosomes in a sample of cells and is used to identify genetic abnormalities associated with first trimester spontaneous abortions. Chromosome analysis test can count the number of chromosomes present as well as look for any structural abnormalities in the chromosomes of the sample cells.
Fluorescence In Situ Hybridization (FISH)
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It is a sensitive method for detecting specific genes or parts of genes. It can detect the most common aneuploidy in uncultured amniocytes (fetal cells in amniotic fluid) within 24-48 hours, making it a rapid and reliable assay for detecting chromosomal abnormalities. FISH technology complements routine chromosome analysis to diagnose common chromosomal disorders.
Microarray
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This test can identify deletions and duplications of chromosome regions and whole chromosomes and it can be performed directly on DNA from POC tissue without cell culturing. The test result may identify the likely cause of a pregnancy loss.
Factors that increase a woman’s risk of having RPOC
Placenta attached too deeply to the wall of the uterus
In a previous pregnancy placenta was left behind in the uterus
Advanced maternal age (>35)
Delivery, miscarriage, or abortion
Prolonged labor lasting more than 14 hours
Previous C-section or uterine surgery
Congenital uterine anomaly
Interpretation of the Test Results
- The POC test screens for the presence of 46 chromosomes and determines if a chromosomal abnormality is present or not. In a healthy fetus, all cells should have two copies of each chromosome with a total of 23 pairs of chromosomes.
- Chromosomal abnormalities, caused by missing or extra chromosomes, can result in a pregnancy affected with a chromosomal syndrome, a miscarriage or recurrent miscarriage.
- Detection of chromosomal abnormalities like aneuploidy or unbalanced structural rearrangement such as trisomy conditions (Patau syndrome, Trisomy 16) and monosomy X (Turners syndrome) using chromosomal analysis, FISH or microarray may explain the cause of miscarriage or stillbirth.
- If abnormalities are present, they are explained in a paragraph in the final report which helps to clarify and correlate chromosomal findings with the cause of pregnancy loss. Genetic counseling is recommended when abnormal results are found along with recommendation for further testing.
FAQs
What is the turnaround time (TAT) for the results of a POC test?
The results of the test can take 15-20 days, although it could take longer at times.
Why is maternal cell contamination testing done during a POC test?
POC testing uses karyotyping, FISH, and microarrays to look for chromosomal abnormalities in the cells taken from the placenta, umbilical cord, or internal organs of the fetus. The maternal cell contamination (MCC) test is performed on mother’s blood samples and fetal tissue to exclude the presence of maternal cells in the fetal sample, presence of which may cause prenatal misdiagnosis.
What are the limitations of chromosome analysis on POC?
One of the major limitations with chromosome analysis on POC is the tissue viability (chance of survival). More than 50% of loss of fetus in early pregnancy have chromosomal abnormalities, failure to get chromosome results can have significant clinical implications for the parents. Decreased viability can contribute up to 25% of samples not getting any chromosome results. However, rapid FISH analysis can overcome this tissue viability limitation since interphase FISH analysis (detects chromosome abnormalities in uncultured cells) can be performed on non-viable tissues.
What are the risks involved in the endometrial biopsy process for retained POC?
During and after the biopsy procedure, you may experience mild pain, bruising, and bleeding at the biopsy site. Occasionally these complications are significant. Severe bleeding or infection rarely occurs which may require further treatment.
I have had 2 consecutive miscarriages, how can POC testing help me?
The most common cause of early miscarriages is genetic abnormalities, so testing the POC typically confirms the genetic cause of the miscarriage. If you have had multiple miscarriages, POC testing is not only helpful for you to understand why the miscarriages are happening but may also provide you with actionable information to improve the success of future pregnancies.
Related tests
Products of Conception (POC) Karyotyping reflex to Fish ( 5 Probes )
₹ 9,000-
Includes
1 Test Parameter(s)
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The major cause of pregnancy loss is due to fetal chromosomal aberrations. Karyotyping of the products of conception (POC) assay helps in diagnosing chromosomal causes of fetal death and determining recurrence risk for future pregnancy losses. Karyotyping is a test to examine chromosomes. Chromosomes are thread-like structures that constitute an individual's DNA and genetic makeup. Karyotyping has been the gold standard method for analyzing POC samples. Karyotyping helps identify both the structural (translocations, deletions, and inversions) and the numerical chromosomal abnormalities. Chromosomal abnormalities may result in malformed fetuses, spontaneous abortions, or neonatal deaths. Fluorescent in situ hybridization (FISH) offers a rapid diagnosis of chromosomal alterations from POC specimens. FISH combined with karyotyping will cover all chromosomal alterations in POC samples.