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81424M
PRENATAL ANEUPOIDY DETECTION, FLUORESCENCE IN SITU HYBRIDIZATION (FISH)

Test Code 81424M 
Test PRENATAL ANEUPOIDY DETECTION, FLUORESCENCE IN SITU HYBRIDIZATION (FISH) 
Methodology Fluorescence In Situ Hybridization (FISH) 
Description Standard chromosome analysis takes about 7 - 9 days for culture, harvest, and analysis for amniotic fluid cells. In cases of medical urgency, FISH analysis can be used to detect chromosome aneusomy of 13, 18, 21, X, and Y within 24 hours (processing time of 6 hours) from uncultured amniotic fluid cells.

NOTE: This test, when ordered on Medicare patients, is subject to the CMS Medicare Coverage Issues Manual (MCIM) Diagnostic Services policy "Cytogenetic Studies". Please verify that the diagnosis code (ICD-9) you have chosen demonstrates medical necessity for the test as documented in the physician's patient record. The CMS web site or the NorDx Limited Coverage Documentation Guide are available to assist you with this verification. A properly executed Advance Beneficiary Notice (ABN) must be submitted with the specimen if medical necessity is not demonstrated by the ICD-9 code chosen. 

Specimen NOTE: Please complete a Cytogenetics/AFP Congenital Disorders Request Form and forward it with the specimen.

SUBMIT ONLY 1 OF THE FOLLOWING SPECIMENS:
PREFERRED:
AMNIOTIC FLUID
Optimum timing for specimen collection is during 16th-18th weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Draw 20-25 mL of amniotic fluid in a sterile syringe (we strongly recommend Pharmaseal amniocentesis tray distributed by Cardinal Health Company). Discard the first 2.0 mL of amniotic fluid, and send the remainder to the laboratory. When using a Pharmaseal Amniocentesis Kit, transfer the amniotic fluid
into the provided transport containers. If Pharmaseal amniocentesis tray is not available, use a Becton-Dickinson syringe; and transport specimen as follows. Remove needle and transfer the specimen to 2 screw-capped, sterile 15-mL centrifuge tubes. Place the tubes in a Styrofoam container (Supply T329). Fill remaining space with packing material. Unavoidably, about 1-2% of mailed-in specimens are not viable. Bloody specimens are undesirable. If the specimen does not grow in culture, you will be notified within 7 days of receipt. Label container with patient's name and laboratory control number. Send specimen refrigerated. SPECIMEN CANNOT BE FROZEN.

ALTERNATE:
CHORIONIC VILLUS
Obtain 20-30 mg of a chorionic villus specimen (CVS) by the
transabdominal or transcervical method. Transfer the CVS to a Petri dish containing transport medium. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi; and remove any blood clots and maternal decidua. Transfer the CVS by using sterile technique to one or two 15-mL centrifuge tube(s) with 15 mL of transport medium. (Petri dishes and transport medium are supplied by NorDx.) Label the centrifuge tube(s) with patient's name and laboratory control number. Send specimen refrigerated. SPECIMEN CANNOT BE FROZEN. 

Reference Values An interpretive report is provided. 
Analytic Time 1 - 2 Days 
Day(s) Test Set Up Monday through Sunday 
CPT Code(s) 88271 x 5  DNA probe, each
88275  Interphase in situ hybridization
88291  Interpretation and report