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Interpretive Handbook

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Test 81081:
Aneuploidy Detection, Products of Conception (POC), FISH

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Products of conception (POC) are tissues created at conception that spontaneously miscarry; these tissues include chorionic villi, fetal membranes, or fetal tissue. Spontaneous miscarriages occur in 15% to 20% of all recognized human conceptions. While there are many possible causes for miscarriages, chromosome anomalies can be identified in up to 50% of first-trimester miscarriages. It is important to determine a possible chromosomal cause of the pregnancy loss as this information impacts patient management and facilitates understanding of the reason for the loss.

 

Chromosomal aneuploidy, the gain or loss of chromosomes, is a major cause of early fetal demise. Trisomy is the most common type of chromosome abnormality in spontaneous abortions and has been observed for most chromosomes, with 13, 15, 16, 18, 21, 22, X, and Y being the most common.

 

Conventional chromosome analyses of POC (#8887 Chromosome Analysis, Autopsy, Products of Conception, or Stillbirth) is a commonly performed method used to identify these common chromosome aneuploidies. Conventional chromosome analysis involves fibroblast cultures. Unfortunately, 20% of POC specimens fail to grow when cultured. A FISH method has been developed to analyze this subset of cases or to be used when fresh tissue is not available for full chromosome analysis.

Useful For Suggests clinical disorders or settings where the test may be helpful

Screening for the common chromosomal aneuploidies (13, 15, 16, 18, 21, 22, X, and Y) in POC when fresh tissue is not available for full chromosome analysis

 

Rapid detection of common chromosomal aneuploidies or triploidy

 

Determining the genetic cause of a miscarriage

Interpretation Provides information to assist in interpretation of the test results

Aneuploidy is detected when the percent of cells with an abnormality exceeds the normal reference range for any given probe.

 

An interpretive report is provided.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test has not been approved by the FDA and is best used as an adjunct to existing clinical and pathological information.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

Warburton D, Byrne J, Canki N: Chromosome anomalies and prenatal development: An atlas. In Oxford Monographs on Medical Genetics. New York, Oxford University Press, 1991, pp 2-3, 57-62