Test Catalog

Test Id : CHRAF

Chromosome Analysis, Amniotic Fluid

Useful For
Suggests clinical disorders or settings where the test may be helpful

Prenatal diagnosis of chromosome abnormalities, including aneuploidy (ie, trisomy or monosomy) and balanced rearrangements

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

Cultures from this specimen will be discarded 10 days after all cytogenetic test results have been reported. If further testing is desired, call the laboratory at 507-284-1668.

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
_ML15 Metaphases, <15 No, (Bill Only) No
_M15 Metaphases, 15 No, (Bill Only) No
_MG14 Metaphases, >15 No, (Bill Only) No
_COL1 Colonies, 1-5 No, (Bill Only) No
_COL6 Colonies, 6+ No, (Bill Only) No
_KTG1 Karyotypes, >1 No, (Bill Only) No
_STAC Ag-Nor/CBL Stain No, (Bill Only) No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test includes a charge for cell culture of fresh specimens and professional interpretation of results. Analysis charges will be incurred for total work performed, and generally include 2 banded karyograms and the analysis of 20 metaphase cells. If no metaphase cells are available for analysis, no analysis charges will be incurred. If additional analysis work is required, additional charges may be incurred.

 

The following algorithm is available:

-Prenatal Aneuploidy Screening and Diagnostic Testing Options

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Cell Culture Followed by Chromosome Analysis

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Chromosomes, Amniotic Fluid

Aliases
Lists additional common names for a test, as an aid in searching

Amniotic Fluid, Chromosome Analysis

Chromosome Analysis, Amniotic Fluid

Karyotype, Amniotic Fluid

Prenatal Chromosomes, Amniotic Fluid

Fetal Aneuploidy

Fetal Chromosome Analysis

DNA Screening for Fetal Aneuploidy

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test includes a charge for cell culture of fresh specimens and professional interpretation of results. Analysis charges will be incurred for total work performed, and generally include 2 banded karyograms and the analysis of 20 metaphase cells. If no metaphase cells are available for analysis, no analysis charges will be incurred. If additional analysis work is required, additional charges may be incurred.

 

The following algorithm is available:

-Prenatal Aneuploidy Screening and Diagnostic Testing Options

Specimen Type
Describes the specimen type validated for testing

Amniotic Fld

Ordering Guidance

Portions of the specimen may be used for other tests such as measuring markers for neural tube defects (eg, AFPA / Alpha-Fetoprotein, Amniotic Fluid), molecular genetic testing, biochemical testing, and FISH testing (including PADF / Prenatal Aneuploidy Detection, FISH). If additional molecular genetic or biochemical genetic testing is needed, order CULAF / Amniotic Fluid Culture/Genetic Testing so that amniocyte cultures may be set up specifically for the use in these tests.

Shipping Instructions

Advise Express Mail or equivalent if not on courier service.

Necessary Information

Provide a reason for referral and gestational age with each specimen, and verify the specimen source. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.

ORDER QUESTIONS AND ANSWERS

Question ID Description Answers
CG765 Reason for Referral
CG766 Specimen

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Supplies: Refrigerate/Ambient Shipping Box, 5 lb (T329)

Specimen Type: Amniotic fluid

Submission Container/Tube: Centrifuge tube

Specimen Volume: 20-25 mL

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.

2. Discard the first 2 mL of amniotic fluid.

3. Place the tubes in a Refrigerate/Ambient Shipping Box, 5 lb (T329).

4. Fill remaining space with packing material.

Additional Information:

1. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.

2. If the specimen does not grow in culture, you will be notified within 7 days of receipt.

3. Bloody specimens are undesirable.

 

Supplies: Refrigerate/Ambient Shipping Box, 5 lb (T329)

Specimen Type: Fetal body fluid

Container/Tube: Sterile tube

Specimen Volume: Entire specimen

Collection Instructions:

1. Place the tubes in a Refrigerate/Ambient Shipping Box, 5 lb (T329).

2. Fill remaining space with packing material.

Additional Information:

1. If the specimen does not grow in culture, you will be notified within 7 days of receipt.

2. Clearly indicate on tube and paperwork that specimen is fetal body fluid.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

Amniotic Fluid: 12 mL; Fetal Body Fluid: NA; If ordering in conjunction with other testing: If ordered with PADF: 14 mL, with CMAP: 24 mL, with PADF and CMAP: 26 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Amniotic Fld Refrigerated (preferred)
Ambient

Useful For
Suggests clinical disorders or settings where the test may be helpful

Prenatal diagnosis of chromosome abnormalities, including aneuploidy (ie, trisomy or monosomy) and balanced rearrangements

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

Cultures from this specimen will be discarded 10 days after all cytogenetic test results have been reported. If further testing is desired, call the laboratory at 507-284-1668.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test includes a charge for cell culture of fresh specimens and professional interpretation of results. Analysis charges will be incurred for total work performed, and generally include 2 banded karyograms and the analysis of 20 metaphase cells. If no metaphase cells are available for analysis, no analysis charges will be incurred. If additional analysis work is required, additional charges may be incurred.

 

The following algorithm is available:

-Prenatal Aneuploidy Screening and Diagnostic Testing Options

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Chromosome analysis for prenatal diagnosis is appropriate in pregnancies with abnormal maternal screening, advanced maternal age, and features suggestive of or concerns for aneuploidy syndromes, including Down syndrome, Turner syndrome, Klinefelter syndrome, trisomy 13 syndrome, and trisomy 18 syndrome.

 

Chromosomal abnormalities are the cause of a wide range of disorders associated with birth defects and congenital diseases. Many of these disorders can be diagnosed prenatally by analysis of amniocytes. This method permits diagnosis of chromosome abnormalities during the second trimester of pregnancy or later.

 

A chromosomal microarray (CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling) is recommended, rather than chromosomal analysis, to detect clinically relevant gains or losses of chromosomal material in pregnancies with 1 or more major structural abnormalities. Chromosomal microarray can also be considered, rather than chromosome analysis, for patients undergoing invasive prenatal diagnostic testing with a structurally normal fetus.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretative report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

Cytogenetic studies on amniotic fluid are considered nearly 100% accurate for the detection of large fetal chromosome abnormalities. However, subtle or cryptic abnormalities involving microdeletions usually can be detected only with the use of targeted FISH testing.

 

Approximately 3% of amniotic fluid specimens analyzed are found to have chromosome abnormalities. Some of these chromosome abnormalities are balanced and may not be associated with birth defects.

 

A normal karyotype does not rule out the possibility of birth defects, such as those caused by submicroscopic cytogenetic abnormalities, molecular mutations, and other environmental factors (ie, teratogen exposure). For these reasons, clinicians should inform their patients of the technical limitations of chromosome analysis prior to performing the amniocentesis.

 

It is recommended that a qualified professional in Medical Genetics communicate all results to the patient.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Interfering factors:

-Improper syringes or transport vessels may be unsuitable to amniotic cells. Amniotic fluid should not be exposed to the syringe plunger tip for longer than a few seconds and fluid should be transferred to a transport (centrifuge) tube as soon as possible following collection.

-Transport time should not exceed 2 days.

-A bloody specimen may interfere with attempts to culture cells and contamination by maternal cells may cause interpretive problems.

-Inadequate amount of fluid may not permit adequate analysis.

-Improper packaging may result in broken, leaky, and contaminated specimen during transport.

-Exposure of the specimen to temperature extremes (freezing or >30 degrees C) may kill cells and severely interferes with attempts to culture cells.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. American College of Obstetricians and Gynecologists Committee on Genetics: Committee Opinion No. 581: the use of chromosomal microarray analysis in prenatal diagnosis. Obstet Gynecol 2013;122:1374-1377

2. Society for Maternal-Fetal Medicine (SMFM): The use of chromosomal microarray for prenatal diagnosis. Am J Obstet Gynecol. 2016;215:B2-B9

3. Committee Opinion, 640: Cell-free DNA screening for fetal aneuploidy. American College of Obstetricians and Gynecologists Committee on Genetics. Obstet Gynecol  2015;123:e31-e37

4. Wilson KL, Czerwinski JL, Hoskovec JM, et al: NSGC practice guideline: prenatal screening and diagnostic testing options for chromosome aneuploidy. J Genet Couns 2013;22:4-15

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

The specimen is centrifuged and the cell pellet is mixed with culture media, then split into 6 primary culture dishes and a T-flask to establish cultures. Cells are harvested after 5 to 7 days. In the harvest process, the cells are exposed to ethidium bromide, colcemid, and hypotonic solution, and fixed with glacial acetic acid and methanol. Metaphase cells are dropped onto microscope slides and are routinely stained by G-banding, but other staining methods may be employed as needed. Fifteen metaphases from 15 colonies and 3 or more primary cultures usually are examined. In cases where true mosaicism is suspected, up to 30 colonies and up to 6 primary cultures may be analyzed. Minimal evidence for the presence of an abnormality is defined as 2 or more metaphases with the same structural abnormality, chromosome gain (trisomy), or 3 or more metaphases lacking the same chromosome. Five or more digitized images of metaphases are stored in computer-based imaging systems and karyograms are prepared from 2 or more representative metaphases.(Chang HC, Jones OW: Amniocentesis: cell culture of human amniotic fluid in a hormone supplement. Cold Springs Harb Conf Cell Prolif 1982;9:1187-1192; Hsu LY, Perlis TE: United States survey on chromosome mosaicism and pseudomosaicism in prenatal diagnosis. Prenat Diagn 1984;4:97-130; Peakman DC, Moreton MF, Corn BJ, Robinson A: Chromosomal mosaicism in amniotic fluid cell cultures. Am J Hum Genet 1979;31:149-155; Spurbeck JL, Carlson RO, Allen JE, Dewald GW: Culturing and robotic harvesting of bone marrow, lymph nodes, peripheral blood, fibroblasts, and solid tumors with in situ techniques. Cancer Genet Cytogenet 1988;32:59-66)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

10 to 11 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Any remaining supernatant or whole fluid aliquots are discarded 14 days after results are reported.

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

88235, 88291-Tissue culture for amniotic fluid or chorionic villus cells, Interpretation and report

88269 w/modifier 52-Chromosome analysis, in situ for amniotic fluid cells, <6 colonies, 1 karyotype with banding (if appropriate)

88269-Chromosome analysis, in situ for amniotic fluid cells, 6 or greater colonies, 1 karyotype with banding (if appropriate)

88267, 88285-Chromosome analysis, amniotic fluid or chorionic villus, greater than 15 cells, 1 karyotype with banding (if appropriate)

88267 w/modifier 52-Chromosome analysis, amniotic fluid or chorionic villus, <15 cells, 1 karyotype with banding (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
CHRAF Chromosomes, Amniotic Fluid 62351-2
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
52297 Result Summary 50397-9
52299 Interpretation 69965-2
52298 Result 82939-0
CG765 Reason for Referral 42349-1
CG766 Specimen 31208-2
52300 Source 31208-2
52302 Method 85069-3
52301 Banding Method 62359-5
54640 Additional Information 48767-8
52303 Released By 18771-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports