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Karyotyping & FISH for Chromosome 18

Omics test Model
Test Code FPC05C
Test Summary Karyotyping - Provides holistic picture of the 23 pairs of chromosome allowing simultaneous examination of all chromosomes. Fluorescence in situ hybridization (FISH) is performed for aneuploidy detection of chromosome 18
Turn Around Time 15 days
Acceptable Sample Types Products of Conception
NY Approved No
Accreditations CAP , ISO 15189 (NABL)
*TAT starts after the sample and all required sample information is received at the processing laboratory.

**The CPT codes listed are in accordance with Current Procedural Terminology, a publication of the American Medical Association, and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party.

This testing service has not been cleared or approved by the U.S. Food and Drug Administration. Testing services may not be licensed in accordance with the laws in all countries. The availability of specific test offerings is dependent upon laboratory location.
This test is not available in your region United States, please select your nearest laboratory to request more information.
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Test Description

A karyotype test is a type of genetic testing. It looks at the size, shape, and number of chromosomes in a sample of cells from your body. Chromosomes are found in the cell nucleus, which is like the command center of a cell. Chromosomes contain your genes. Genes carry information, called DNA, that controls what you look like and how your body works.You inherit your chromosomes from your parents. Normally, all your cells (except for egg and sperm cells) have a set of the same 46 chromosomes. The chromosomes are grouped into 23 pairs. Each pair has two chromosomes, one coming from each parent. You may develop certain genetic disorders if your cells:

  • Are missing whole chromosomes or pieces of chromosomes
  • Have extra chromosomes or extra pieces of chromosomes

FISH - Rapid detection of aneuploidy involving chromosome 18. Assay offered in conjunction with chromosome study.

Indications for Testing


  • Abnormal fetal ultrasound and presenceof soft markers like hypoplastic nasal bone, Increased NT, Echogenic bowel etc.
  • Maternal serum screening positive for chromosome aneuploidies
  • NIPT positive for chromosome aneuploidies
  • Parental chromosomal rearrangement or mosaicism
  • Previous history of recurrent miscarriages
  • Previous fetus/baby with chromosoma abnormality


The FISH analysis does not detect structural chromosome abnormalities, mosaicism, and other numerical chromosome abnormalities (excluding 13, 18, and 21). The American College of Medical Genetics recommends that irreversible therapeutic action should not be initiated on the basis of FISH results alone.

Condition Description


A karyotype test looks for unusual changes in chromosomes. It may be used to:

  • Check an unborn baby for chromosome problems
  • Check you and/or your family members for specific chromosome problems if you:
    • Have a genetic disorder that runs in your family
    • Have symptoms that may be from a genetic disorder
  • Find out if abnormal chromosomes are causing problems having children, including:
    • Male or female infertility
    • Miscarriages, if you have lost two or more pregnancies before 20 weeks
    • Stillbirth
    • Help diagnose and/or make treatment decisions for certain types of cancer and blood disorders


  • Screening result suggests aneuploidy
  • Advanced maternal age
  • One major or at least two minor fetal structural defects found on ultrasound
  • Previous fetus or child with aneuploidy
  • Parent of this pregnancy has a structural chromosome abnormality (e.g.,translocation, inversion) involving chromosome 18

Test Methods and Limitations

Karyotyping - Chromosomal Analysis / Light Microscopy

FISH - Fluorescence in situ hybridization (FISH) Fluorescence Microscopy

Detailed Sample Requirements

Products of Conception
Test Details Page
Collection Container(s) Sterile, screw-top container filled with tissue culture transport medium.

All prenatal specimens will be tested for maternal cell contamination (MCC). Send maternal blood (EDTA tube) for comparison. Transport products of conception and/or fresh tissue (minimum: 10 mg) in a sterile, screw-top container filled with tissue transport medium. Do not place in formalin. If the specimen is too large for a normal collection tube, a larger sterile container can be used.

Sample Condition If the autopsy is performed: Facia lata, diaphragm, tendon, skin, tissue from internal organs (if fresh), chest wall cartilage (particularly if macerated), or placenta from fetal side. If no autopsy is performed: Placenta from fetal side is preferred, e.g., villi. Umbilical cord is also acceptable. State clearly in the TRF whether the tissue was of fetal or placental in origin.
Shipping Shipped immediately at ambient temperature or with a cold pack, especially under hot weather to the laboratory by overnight express with arrival Monday-Friday only. Alternatively, fresh POC and/or tissue samples can be snap-frozen and kept at -80°C. Frozen tissue samples should be shipped overnight on dry ice with arrival Monday-Friday only - NO WEEKEND SHIPMENTS!
Special Sample Instructions For prenatal samples, Revvity Omics will provide a shipping label to use for shipping the sample to our lab. Please call 1 (866) 354-2910 to arrange this. At this time, you will also be connected to a laboratory genetic counselor to answer any questions about the testing. For samples originating outside of the United States, please contact your nearest Revvity Omics laboratory for more information.