Cytogenetics Laboratory

Available on-call for weekend emergencies.

Contact on-call cytogenetic technologist PIC# 1580

SPECIMEN COLLECTION

Specimens are handled through Specimen Receiving or Monday through Friday 8-4 samples can be tubed directly to Davis Lab (tube # 520). It is important that the sample be properly bagged and labeled "Cytogenetics Laboratory," to eliminate any confusion.

The laboratory provides the usual range of cytogenetic studies with a variety of banding techniques plus numerous specialized studies. If there are any questions, call the supervisor before collecting a sample. A cytogenetic laboratory request form must be submitted with each sample. All clinical data should be listed. For most of the constitutional study requests, a non-malignant genetic consult is suggested (Genetics Division - 924-2665).

1. Peripheral Lymphocyte Karyotype: Indicated for suspected Down Syndrome, Turner Syndrome, Klinefelter Syndrome and chromosomal aneuploidies or unbalanced states; detection of balanced chromosomal rearrangements in infertility, repeated fetal wastage and family history of a chromosomal rearrangement and such conditions as retinoblastoma, Prader-Willi Syndrome and other suspected subtle rearrangements. Mention specific clinical indications on cytogenetics request form. This test involves G-banded (Giemsa) analyses of 20 metaphases with karyotypic analysis of these cells. Study requires 2-4 weeks.

A STAT blood study for gross structural or numerical abnormalities can have a preliminary result in 48-72 hours. Please indicate if this is requested.

Submit a sodium heparin green top tube or heparinized blood sample in syringe.  Obtain 5-10 cc by sterile procedure. Less blood (1-2 cc) is adequate for neonate.

2. Fibroblast Cultures: For study of suspected mosaicism when lymphocyte karyotype is normal or ambiguous, or when blood is unavailable (abortion, stillbirth, autopsy) or when cell line build up is desired, any sterile fibrous tissue can be used. In addition to skin other preferred tissue types are pericardium, villi, placenta. They should be obtained as sterilely as possible and placed in culture media. Media is available from the lab or in the postmortem suite. If media is not available, sterile saline can be used. Study requires 4-6 weeks for completion.

3. Bone Marrow Karyotype: Indicated in diagnostic evaluation of suspected leukemia and other malignancies. 1-3 cc of bone marrow may be collected in heparinized syringe or put in a small sodium heparin green top vacutainer and send to lab immediately. In cases where marrow is not available and circulating blasts are present, a peripheral blood sample may be sent (5 ml in green top sodium heparin vacutainer). Study requires 7-14 days.

4. Amniotic Fluid Cell Study: Indicated for prenatal diagnosis of genetic disorders detectable by cell culture techniques. 20-30 ml of amniotic fluid obtained sterilely is needed. Study requires 10-14 days.

5. Chorionic Villus Sampling Studies: Indicated for prenatal diagnosis of genetic disorders detectable by cell culture techniques. 20 or more mg of villi obtained sterilely is needed. Study requires 10-14 days.

6. Chromosomal Analysis of Malignancies: In addition to bone marrow cells in leukemia, cytogenetic abnormalities characterize most malignant cell lines. These can be analyzed from peritoneal fluid, suspensions or solid tumors. The solid tumors that are indicated for study include: Ewing Sarcoma, Rhabdomyosarcoma, synovial sarcomas, medulloblastomas, Wilms tumors, uterine leiomyoma, leiomyosarcomas, and neuroblastomas. A small fresh tumor tissue sample collected in media in a sterile tube or container is required. Media is available from the laboratory or sterile saline may be used. Study requires 1-3 weeks.

7.  Special Studies: These are some of the studies which require special media and culture techniques.  These special studies must be indicated on chromosome request forms.

8. Fluorescent in situ hybridization (FISH Studies): The laboratory performs a variety of analyses using FISH methodology. Chromosome rearrangements commonly found in malignancies can be tested for using interphase nuclei and specific test probes. Many probes for analysis of a variety of hematopoietic disorders are available including CML, AML, ALL, CLL, MDS, Lymphoma and multiple myeloma. This test takes 2-7 days to complete. Constitutional microdeletion syndromes such as Prader-Willi, Angelman and Williams are tested for using metaphase preparations. Call laboratory supervisor for current availability of probes to be utilized in fluorescent in situ hybridization analysis.

9. Chromosomal Microarray Analysis (CMA): Indicated for patients with developmental delay, dysmorphic features, autism spectrum disorder, etc.  Analysis can detect microdeletions or microduplications not visible with standard karyotype analysis.  CMA can also be used to help define genes involved in an already identified deletion, duplication, or unbalanced translocation.  Study requires a minimum of 2 mL blood collected in an EDTA (purple top) tube and 2 mL blood collected in a sodium heparin (dark green top) tube.  Both samples must be collected for analysis.  Please provide clinical indication on test request form.  CMA requires 2-4 weeks to complete.