Warnings & Limitations

1. The AneuVysion kit has been characterized only for identifying targeted regions of chromosomes X, Y, 18, 13, and 21 in interphase nuclei from uncultured and cultured amniocyte specimens.
2. The clinical interpretation of any test result(s) should be made in conjunction with other diagnostic laboratory test results and should be evaluated within the context of the patient’s medical history and current risk factors. Patient management decisions should be made based on information from two of three of the following parameters: FISH results, routine chromosome analysis, or clinical information.¹
3. FISH assay results may not be informative if the specimen quality and/or specimen slide preparation is inadequate.
4. This assay will not detect the presence of structural abnormalities frequently associated with birth defects. The frequency of these occurrences may be population and gestational age dependent.
5. This assay should not be performed on amniocyte specimens with moderate to severe maternal cell contamination. FISH test results on amniocyte specimens with mild maternal cell contamination should be interpreted with caution.
6. No irreversible therapeutic action should be initiated based on the FISH assay alone. Positive results should be further characterized using traditional chromosome analysis to determine the mutational mechanism accounting for the abnormality detected by FISH. This information may aid in counseling for the risk that the detected abnormality may occur in future pregnancies.¹
7. Physicians, counselors, and other healthcare providers should understand the risk of abnormalities that the test is not designed to detect. The patient should be informed that there is still a very small risk of low level mosaicism, cryptic translocations, or other undetectable events that may not be demonstrated by FISH or standard cytogenetics. Additionally, there is a very small risk that some individuals carry a genetic polymorphism that may affect the intensity, presence or absence of the probe signal that may result in a missed diagnosis.¹⁷
8. When the specimen volume is not suffi cient to meet the minimum requirements for processing both FISH and standard cytogenetic procedures, the user must carefully weigh the risks and benefi ts of utilizing any material for FISH. Consultation between the laboratory geneticist and/or genetic counselor and the patient’s physician may aid in clarifying what information is desired, and which testing method should be used.¹
9. Technologists performing the FISH signal enumeration must be capable of visually distinguishing between the orange, green and aqua signals.
10. Although the probe for enumerating chromosome 13 spans the Rb1 locus, this probe has not been validated for detecting mutations associated with retinoblastoma. In rare cases, the Rb1 locus may be deleted; this could complicate interpretation of FISH test results.

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References

^1. American College of Medical Genetics. Technical and clinical assessment of fluorescence in situ hybridization: an ACMG/ASHG position statement. I. Technical considerations. Genetics in Medicine 2000;2(6):356-361.
^17. Tepperberg J, Pettenati MJ, Rao PN, Lese CM, Rita D, Wyandt H, Gersen S, White B, Schoonmaker MM. Prenatal diagnosis using interphase fluorescence in situ hybridization (FISH): two-year multi-center retrospective study and review of the literature. Prenat Diagn 2001;21(4):293-301.