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Laboratory Test Directory

Chromosome Analysis, Amniotic Fluid


Name Method Department Units
Amniotic Fluid Chromosome Analysis, Standard Chromosomal analysis
Cell Culture

Specimen Requirements

Amniotic fluid

Container Type Container Size Specimen Volume

Sterile container

N/A 20 mL-35 mL

Room temperature - 24 hour(s)

Specimen Preparation

  • Do not add fixative
  • Do not centrifuge
  • Do not freeze
  • Do not refrigerate
  • Keep at room temperature

Reasons for Rejection

  • Fixed specimen
  • Frozen specimen
  • Delayed or improper handling
  • Not received within specified time frame
  • Wrong collection tube


Submission of a completed Prenatal Genetic Test Requisition Form is required. To obtain the form, please call Cytogenetics Lab at (614) 722-5321.

This test is used to evaluate fetal chromosomes for numerical and gross structural abnormalities (e.g. translocations, inversions). Common indications for study include advanced maternal age, abnormal prenatal screening test such as maternal serum quad screen or noninvasive prenatal testing/screening (NIPT/NIPS), abnormal fetal ultrasound exam, and family history of chromosome abnormality.

For this test, fetal cells contained in amniotic fluid will be cultured, then cultured metaphase cells will be used to perform chromosome analysis. Cells from 15 colonies will be evaluated for this test, unless poor cell growth prohibits. Extended mosaicism study (performed with extra charges) can also be ordered, which evaluates chromosomes in additional colonies to study for low-level mosaicism for chromosome abnormality. Turnaround time for results varies depending on the rate of cell growth in culture, but results are typically available in 8-10 days.

Please collect minimum of 15 mL amniotic fluid in a non-toxic, sterile container. Transport the sample at room temperature and send to the laboratory within 24 hours from collection time. DO NOT freeze the sample.

  • If Aneuploidy FISH Screen for common aneuploidies (chromosomes 13, 18, 21, X and Y; see test code: GEN3) is also ordered, submit additional 5-10 mL amniotic fluid.
  • If amniotic fluid AFP with reflex to AChE and fetal hemoglobin, infectious disease qualitative PCR, and/or 7-dehydrocholesterol biochemical study (Smith-Lemli-Opitz syndrome testing) is also ordered, submit 2-3 mL additional amniotic fluid. Although direct (unspun) fluid is always preferred, supernatant fluid can also be used as alternate sample for these tests.
  • If Prenatal Microarray Analysis is also desired, please submit maternal sample (4 mL blood in EDTA tube) for maternal cell contamination study. 
  • If additional testing on cultured amniocytes is also ordered (e.g. Send-out cultured cells to another laboratory), submit additional 5-10 mL amniotic fluid and call Cytogenetics Lab to speak with a laboratory genetic counselor to coordinate. For molecular genetic testing to be performed on cultured amniocytes, submission of maternal sample (4 mL blood in EDTA tube) is also recommended to perform maternal cell contamination study.

CPT Code

  • 88235
  • 88267
  • 88280