Test ID: FBUCC
X and Y Aneuploidy Detection, Buccal Smear, FISH
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
As a supplement to conventional cytogenetic analysis in patients with normal or uncertain cytogenetic results for sex chromosome aneuploidy or when an alternative tissue needs to be studied
To screen individuals suspected of having sex chromosome aneuploidy
As a means to rapidly determine the sex chromosome complement
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
This test is only appropriate as a supplement to conventional chromosome studies when an alternative tissue needs to be studied to detect sex chromosome aneuploidy.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Fluorescence In Situ Hybridization (FISH)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Buccal Smear (X and Y Chromatin)
X Chromatin and Y Body
X Chromosome
Y Chromosome
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Provide a reason for referral with each specimen. The laboratory will not delay or reject testing if this information is not provided, but appropriate testing and interpretation may be compromised.
Container/Tube: Buccal Smear Collection Kit (Supply T543)
Specimen Volume: 2 Cyto-Pak brushes
Collection Instructions:
1. Patient should rinse out mouth vigorously with mouthwash followed by water for approximately 15 seconds. Mouthwash is not a requirement but helps reduce the bacteria found in the mouth that may hinder testing.
2. Remove the Cyto-Pak brush from the container only touching the "stick" end. Save the container.
3. Using medium pressure, rotate the brush several times on the inside of the cheek.
4. Return brush to container and cap.
5. Repeat steps 2 through 4 on the other cheek using the second brush.
6. It is important that the patient's buccal cells are not contaminated with cells from any other source. Do not touch the bristles. Do not brush too vigorously. If blood appears, discard the brush and restart the collection process.
7. Label each container with patient's name and order number or hospital/clinic number.
Additional Information:
1. Provide appropriate clinical information about the patient as per specific test requirements.
2. It is important that the cells do not dry out during shipping. Ensure that the container is tightly sealed.
Forms:
1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
2. If not ordering electronically, submit a Cytogenetics/AFP Congenital Disorders Request Form (Supply T238) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Buccal Swab | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Aneuploidy of the sex chromosomes is common among recognized congenital syndromes. For example, the majority (80%) of individuals with Klinefelter syndrome have 2 X chromosomes and 1 Y chromosome; the remainder are mosaics or variants. Individuals with Turner syndrome have a single X chromosome in 55% of cases; the remaining 45% are either variants or mosaics.
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.
XX in females; XY in males
Interpretation Provides information to assist in interpretation of the test results
Specimens that contain >5% cells with a signal pattern other than XX in females and XY in males have a very high likelihood of having a clone of cells with an abnormal complement of sex chromosomes.
Specimens with <5% of cells with a signal pattern other than XX in females and XY in males most likely do not have a clone of cells with an abnormal complement of sex chromosomes, but the presence of an abnormal clone of cells is not completely ruled out.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Conventional cytogenetic analysis should be performed for confirmation, especially when the results are abnormal.
Structural abnormalities of X and Y chromosomes will be missed by this technique, as will low-level mosaicism.
This test can detect between 50% to 70% of Turner syndrome cases (only those caused by complete lack of 1 sex chromosome [45,X] or high-level mosaicism for a 45,X). Congenital blood chromosome analysis (CMS/8696 Chromosome Analysis, for Congenital Disorders, Blood) should always be performed for Turner syndrome.
The test does not rule out numeric or structural cytogenetic anomalies involving chromosomes other than X and Y.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Babovic-Vuksanovic D, Michels VV, Law ME, et al: Guidelines for buccal smear collection in breast-fed infants. Am J Med Genet 1999;84:357-360
Method Description Describes how the test is performed and provides a method-specific reference
Buccal mucosa cells are analyzed for XX (females) and XY (male) sex chromosome complement by using X and Y centromere probes. These probes are hybridized to interphase cells and visualized by fluorescence microscopy using a process called fluorescence in situ hybridization (FISH). Normal female cells will have 2 orange signals signifying hybridization of the X chromosome probe to both X chromosome centromeres. Normal male cells will have a single orange and a single green signal, signifying hybridization of the X chromosome probe to the X centromere and the Y chromosome probe to the Y chromosome centromere, respectively. The number of individual cells is expressed as a percentage of the total number of interphase cells analyzed. Up to 200 cells will be analyzed for the sex chromosome signal pattern. (Schad CR, Kuffel DG, Wyatt WA, et al: Application of fluorescent in situ hybridization with X and Y chromosome specific probes to buccal smear analysis. Am J Med Genet 1996;66:187-192)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m. CST.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
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's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
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 Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88271 x 2-DNA probe, each
88275 x 2-Interphase in situ hybridization
88291-Interpretation and report
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 16071 | Specimen | 31208-2 |
| 16329 | Specimen ID | N/A |
| 16784 | Source | N/A |
| 16072 | Order Date | N/A |
| G_23 | Reason For Referral | 42349-1 |
| 16076 | Method | In Process |
| 16078 | Results | 35129-6 |
| 16079 | Interpretation | 69965-2 |
| 16080 | Amendment | In Process |
| 16081 | Consultant | N/A |
| 16082 | Report Date | N/A |
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