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Test ID: CHRPC Chromosome Analysis, Autopsy, Products of Conception, or Stillbirth

Useful For

Diagnosis of congenital chromosome abnormalities in products of conception, including aneuploidy (ie, trisomy or monosomy)

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
POCRF POC Aneuploidy Detection, FISH Yes No
_M15A Metaphases, 1-14 No, (Bill Only) No
_M19 Metaphases, 15-20 No, (Bill Only) No
_MG19 Metaphases, >20 No, (Bill Only) No
_KTG2 Karyotypes, >2 No, (Bill Only) No
_STAC Ag-Nor/CBL Stain No, (Bill Only) No

Testing Algorithm

This test includes a charge for cell culture of fresh specimens and professional interpretation of results. Analysis charges will be incurred for total work performed, and generally include 2 banded karyograms and the analysis of 20 metaphase cells. If no metaphase cells are available for analysis, no analysis charges will be incurred. If additional analysis work is required, additional charges may be incurred.

 

If the POC chromosome study fails to produce dividing cells, the test will be resulted and Mayo test POCRF / Products of Conception (POC) Aneuploidy Detection, FISH, Fresh Tissue will be automatically reflexed and performed.

Method Name

Cell Culture followed by Chromosome Analysis

Reporting Name

Chromosomes, POC/Fetal Loss

Specimen Type

Tissue


Advisory Information


This test is not appropriate as a first-tier test for detecting gains or losses of chromosomal material in instances of intrauterine fetal demise or stillbirth.



Additional Testing Requirements


In products of conception specimens, maternal cell contamination can interfere with the interpretation of chromosome analysis. To reduce this difficulty, attempt to identify and send only fetal tissue for analysis. If multiple specimen types are sent, send each specimen in a separate container. Multiple specimens received (eg, placenta and fetal thigh) will be ordered under 1 test. All specimens will be processed separately.



Necessary Information


Provide a reason for referral with each specimen. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.



Specimen Required


Preferred:

Supplies: Hank's Solution (T132)

Specimen Type: Products of conception or stillbirth

Container/Tube: Sterile container with sterile Hank's solution (T132), Ringer's solution, sterile RPMI transport media, or normal saline

Specimen Volume: 1 cm(3) of placenta (including 50-mg chorionic villi) and 1 cm(3) biopsy specimen of muscle/fascia from the thigh

Collection Instructions: If a fetus cannot be specifically identified, collect 50-mg villus material or tissue that appears to be of fetal origin.

Additional Information:

1. Do not send entire fetus.

2. While fresher specimens prepared as described above are preferred, we can attempt analysis on specimens that have been in less-than-ideal conditions.

 

Acceptable:

Supplies: Hank's Solution (T132)

Specimen Type: Autopsy

Container/Tube: Sterile container with sterile Hank's solution (T132), Ringer's solution, sterile RPMI transport media, or normal saline

Specimen Volume: 1 cm(3) biopsy specimen of muscle/fascia from the thigh

Collection Instructions:

1. Wash biopsy site with an antiseptic soap.

2. Thoroughly rinse area with sterile water.

3. Do not use alcohol or iodine preparations.

4. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.

 

Alternate:

Supplies: CVS Media (RPMI) and Small Dish (T095)

Specimen Type: Chorionic villus

Container/Tube: 15-mL tube containing 15 mL of transport media

Specimen Volume: 50 mg

Collection Instructions:

1. Collect chorionic villus specimen (CVS) by transabdominal or transcervical method.

2. Transfer CVS to a Petri dish containing transport medium (Such as CVS Media (RPMI) and Small Dish [T095]).

3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of villi and remove any blood clots and maternal decidua.


Specimen Minimum Volume

Chorionic Villus: 10 mg; Muscle-Fascia: 1 cm(3)

Specimen Stability Information

Specimen Type Temperature Time
Tissue Refrigerated (preferred)
  Ambient 

Clinical Information

Chromosome analysis of products of conception, spontaneous abortions, stillborn infants, or neonates is appropriate when previous losses have occurred and features suggestive of or concerns for aneuploidy syndromes, including Down syndrome, Turner syndrome, Klinefelter syndrome, trisomy 13 syndrome and trisomy 18 syndrome. Chromosomal abnormalities may result in malformed fetuses, spontaneous abortions, or neonatal deaths. Estimates of the frequency of chromosome abnormalities in spontaneous abortuses range from 15% to 60%.

 

Chromosome studies of products of conception (POC) may provide useful information concerning the cause of miscarriage and, thus, the recurrence risk for pregnancy loss and risk for having subsequent children with chromosome anomalies.

 

Chromosome analysis of the stillborn infant or neonate (autopsy) may be desirable, particularly if there is a family history of 2 or more miscarriages or when malformations are evident. For neonatal cases, peripheral blood is the preferred specimen for chromosome analysis (CHRCB / Chromosome Analysis, Congenital Disorders, Blood).

 

Some of the chromosome abnormalities that are detected in these specimens are balanced (no apparent gain or loss of genetic material) and may not be associated with birth defects, miscarriage, or stillbirth.

 

For balanced chromosome rearrangements, it is sometimes difficult to determine whether the chromosome abnormality is the direct cause of a miscarriage or stillbirth. In these situations, chromosome studies of the parents' peripheral blood may be useful to determine if an abnormality is familial or de novo. 

 

De novo, balanced rearrangements can cause miscarriages or stillbirth by producing submicroscopic deletions, duplications, or gene mutations at the site of chromosome breakage.

 

A normal karyotype does not rule out the possibility of birth defects, such as those caused by submicroscopic cytogenetic abnormalities, molecular mutations, and environmental factors (ie, teratogen exposure).

-Subtle structural chromosomal abnormalities can occasionally be missed

-Culturing of maternal cells rather than fetal cells

-Chromosome mosaicism may be missed due to statistical sampling error (rare)

 

A chromosomal microarray (CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling) is recommended, rather than chromosomal analysis, to detect clinically relevant gains or losses of chromosomal material in instances of intrauterine fetal demise or stillbirth.

Reference Values

An interpretive report will be provided.

Interpretation

A normal result is a karyotype of 46,XX or 46,XY. A chromosome abnormality known to be pathogenic will be reported as abnormal. Apparently balanced rearrangements will be reported. On rare occasions, structural changes with unknown clinical significance will be identified and reported.

 

Due to bacterial contamination or nonviable cells, we are unable to establish a viable culture 20% of the time. In these cases, the specimen cannot be used for chromosome analysis, and the FISH aneuploidy test (POCRF / Products of Conception (POC) Aneuploidy Detection, FISH, Fresh Tissue) is automatically initiated. While the FISH test is not as comprehensive as a chromosome analysis, it can provide information with regard to the most common numeric abnormalities in spontaneous miscarriage and stillbirth. A FISH signal pattern with 2 signals for 13, 15, 16, 18, 21, 22 and either 2 signals for chromosome X or one signal for chromosome X and one signal for chromosome Y in each interphase will be reported as normal. A FISH signal pattern indicating an additional signal (3 signals) in each interphase will be reported as having a trisomy of the chromosome identified. A FISH signal pattern indicating loss of a signal (1 signal) will be reported as having a monosomy of the chromosome identified. A FISH signal pattern indicating an additional signal for every chromosome (3 signals for X and/or Y and 3 signals for chromosomes 13, 15, 16, 18, 21, 22) will be reported as having triploidy.

Clinical Reference

1. Laurino MY, Bennett RL, Saraiya DS, et al: Genetic evaluation and counseling of couples with recurrent miscarriage: recommendations of the National Society of Genetic Counselors. J Genet Couns 2005;14,165-181

2. American College of Obstetricians and Gynecologists Committee on Genetics: Committee Opinion No. 581: the use of chromosomal microarray analysis in prenatal diagnosis. Obstet Gynecol 2013;122:1374-1377

3. Society for Maternal-Fetal Medicine (SMFM): The use of chromosomal microarray for prenatal diagnosis. Am J Obstet Gynecol. 2016;215:B2-B9

Day(s) and Time(s) Performed

Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m. CST.

Analytic Time

21 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

88233, 88291-Tissue culture for skin/biopsy, Interpretation and report

88262 w/modifier 52-Chromosome analysis less than 15 cells(if appropriate)

88262-Chromosome analysis with 15 to 120 cells (if appropriate)

88262, 88285-Chromosome analysis with greater than 20 cells (if appropriate)

88280-Chromosome analysis, greater than 2 karyotypes (if appropriate)

88283-Additional specialized banding technique (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CHRPC Chromosomes, POC/Fetal Loss In Process

 

Result ID Test Result Name Result LOINC Value
52251 Result Summary 50397-9
52253 Interpretation 69965-2
52252 Result In Process
CG757 Reason for Referral 42349-1
CG758 Specimen 31208-2
52254 Source 31208-2
52256 Method 49549-9
52255 Banding Method 62359-5
54634 Additional Information 48767-8
52257 Released By No LOINC Needed

Forms

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. Final Disposition of Fetal/Stillborn Remains form (if fetal specimen is sent) in Special Instructions (Only for products of conception or stillbirth specimen).

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

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