Prenatal Aneuploidy Detection, FISH
Label Mnemonic: PAD
Epic Lab Code: LAB8135
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Amniotic Fluid or Chorionic Villi
Specimen Instructions:
Amniotic Fluid Collection Instructions:
1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Provide gestational age at the time of amniocentesis.

2. Discard the first 2 mL of amniotic fluid.

Chorionic Villi Collection Instructions:
1. Collect specimen by the transabdominal or transcervical method.

2. Transfer chorionic villi to a Petri dish containing transport medium.

3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.
Minimum:
20-25 mL Amniotic Fluid OR 20-30 mg Chorionic Villi
Turn Around Time:
3 days upon receipt at reference laboratory
Reference Range:
An interpretive report will be provided.
Interpretive Data:
An interpretive report is provided.
Comments:
Please print, complete and submit the Informed Consent for Genetic Testing from Mayo Medical Laboratories with the specimen and the A-1a Miscellaneous Request or Epic Req.

Useful for:
Screening for chromosomal aneuploidies of chromosomes 13, 18, 21, X, and Y in prenatal specimens.

Cautions:
This test does not detect aneuploidy of chromosomes other than 13, 18, 21, X, or Y. This test does not detect other chromosomal or structural anomalies.

Low levels of mosaicism involving chromosomes 13, 18, 21, X, or Y may not be detected by this procedure.

There may be interpretation problems in cases of maternal cell contamination.

The use of these probes has been approved by the FDA as a stand-alone test. However, we would strongly recommend that a complete chromosome analysis or a detailed ultrasound be performed in conjunction with this diagnostic procedure. In cases where the FISH analysis is normal, a chromosome analysis allows identification of more complex abnormalities and the less common numeric abnormalities of other chromosomes. In cases where the FISH study is abnormal, chromosome analysis can determine whether the abnormality is due to aneuploidy or a complex structural abnormality. Conventional chromosome analysis allows calculation of a more accurate recurrence risk for the family.
Methodology:
Fluorescence In Situ Hybridization (FISH)
CPT Code:
88291