Chromosome Analysis, POC Tissue

The entire POC or a portion of the POC containing placental membrane, villi, umbilical cord, and fetal parts is optimal. In cases of early pregnancy loss, membranes and villi may be the only fetal tissue available. In later pregnancy loss, other fetal tissues including umbilical cord, skin, cartilage (rib), pericardium, internal membrane, and diaphragm should also be submitted if available.

Placenta specimens should be collected from the fetal side of the placenta. Amniotic fluid, cord blood, and/or cardiac blood may also be submitted using a different test code. To choose the appropriate test code, or to discuss a particular case with a genomic science specialist, please call Quest Genomics Client Services at 866-GENE-INFO.

POC (products of conception) specimens should be collected in as sterile a manner as possible and immediately placed in transport medium in a sterile urine cup or other sterile container to reduce cell death and contamination. Quest Diagnostics provides "POC Transport Media" upon request (a balanced salt solution supplemented with antibiotics and an antimycotic). However, any sterile, balanced salt solution is acceptable (eg Ringer's solution, Hanks Balanced Salt Solution). The transport media, including Ringer’s solution and Hanks Balanced Salt Solution, should be stored refrigerated (2-8°C). Water is not an acceptable transport medium.

If multiple tissue types are available from a POC, please put each tissue type in its own container. Each container should be clearly labeled with the specific tissue type and patient name. All tissue types can be submitted under the same requisition and test code unless they are from multiple gestations. For multiple gestations, please submit POC from each gestation under separate requisitions. 

To prevent POC specimens from drying out, store and transport the specimens in tightly closed containers. Store the specimens at a refrigerated (2-8°C) temperature. Room temperature storage is not recommended, and specimens should never be frozen. Transport specimens in a sterile, balanced salt solution (eg Ringer's solution, Hanks Balanced Salt Solution) as soon as possible at room temperature, preferably less than 48 hours after collection. 

Any compromised specimens that would fail to produce analyzable metaphase cells (eg, formalin-fixed specimens, frozen samples, necrotic tissue, or obviously contaminated specimens) cannot be used for chromosome study. Chromosome studies can only be performed on dividing cells cultured from fresh tissue specimens.

Please send the patient’s clinical and pregnancy history, any significant family history, and gestational age information. 

Yes, other studies may be appropriate. There are many causes of fetal anomalies, some of which are genetic. In the absence of clinical suspicion for a specific genetic disorder, a microarray analysis may be performed on the products of conception (POC) to detect subtle deletions and duplications (test code 90929, Chromosomal Microarray, POC, ClariSure^® Oligo-SNP). If clinical suspicion exists for a specific disorder, other genetic testing may be available. Please contact Quest Genomics Client Services at 866-GENE-INFO to discuss the case with a genomic science specialist and for information on adding another test. 

No. Please call Quest Genomics Client Services at 866-GENE-INFO to discuss this case with a genomic science specialist. Documentation of the specific genetic abnormality in the family will be necessary to determine the correct interpretation of the testing that was performed on the fetus.

When tissue fails to grow, a standard chromosome analysis is impossible to perform. Two tests may be considered to provide some information regarding the fetal chromosomes on tissue samples that fail to grow. The FISH, Products of Conception Panel (test code 14820) will provide information regarding the number of copies of chromosomes 13, 16, 18, 21, 22, X, and Y.

The Chromosomal Microarray, POC, ClariSure^® Oligo-SNP (test code 90929) test may detect subtle deletions and duplications of chromosome material. Please contact Quest Genomics Client Services at 866-GENE-INFO to discuss the case with a genomic science specialist and for information on adding additional testing. 

The test rules out the following chromosome abnormalities:

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• Trisomies such as Down syndrome, trisomy 18, and trisomy 13
• Sex chromosome abnormalities such as Turner syndrome and Klinefelter syndrome
• Most rearrangements, such as Robertsonian translocations and inversions
• Marker chromosomes
• Mosaicism above 14% (at a 95% confidence level)

• Most microdeletion syndromes, such as DiGeorge, Prader-Willi, Angelman, Williams, and Smith-Magenis
• Subtle rearrangements and small gains/losses
• Mosaicism below 14%
• Single gene disorders, such as fragile X syndrome, cystic fibrosis, Marfan syndrome, neurofibromatosis

Yes. Maternal Cell Contamination Study, STR Analysis (test code 10262) may be ordered on a maternal blood sample. Ideally, the maternal sample should be submitted with the tissue sample so that the tissue sample can be prepared for the MCC study to be initiated promptly upon completion of the chromosome analysis. If you are considering adding MCC studies to a completed case, please call Quest Genomics Client Services at 866-GENE-INFO to speak with a genomic science specialist.