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Test Code FXS Fragile X Syndrome, Molecular Analysis, Varies

Important Note

Cerner Order Name:    Fragile X Syndrome, Molecular Analysis-M
 

Useful For

Confirming a diagnosis of fragile X syndrome, fragile X tremor/ataxia syndrome, or premature ovarian insufficiency caused by expansions in the FMR1 gene

 

Determining carrier status for individuals with a family history of fragile X syndrome or X-linked intellectual disability

 

Prenatal diagnosis of fragile X syndrome when there is a documented FMR1 expansion in the family

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULFB Fibroblast Culture for Genetic Test Yes No
CULAF Amniotic Fluid Culture/Genetic Test Yes No
MATCC Maternal Cell Contamination, B Yes No
FUFXS Fragile X, Follow up Analysis No No

Testing Algorithm

When this test is ordered, fragile X follow-up analysis testing will be performed and charged dependent upon the reported sex of the individual and on the size of the CGG repeat found by polymerase chain reaction analysis.

 

When sending in prenatal specimens:

-If amniotic fluid (nonconfluent cultured cells) is received, amniotic fluid culture will be added at an additional charge.

-If chorionic villus specimen (nonconfluent cultured cells) is received, fibroblast culture for genetic test will be added at an additional charge.

For any prenatal specimen that is received, maternal cell contamination studies will be added.

Method Name

Polymerase Chain Reaction (PCR)

Reporting Name

Fragile X Syndrome, Mol. Analysis

Specimen Type

Varies


Ordering Guidance


Due to the complexity of prenatal testing, consultation with the laboratory is required. To speak with a genetic counselor about this testing option, call 800-533-1710.

 

FMR1-methylation status cannot be assessed on chorionic villus specimens. Contact a molecular genetic counselor/consultant at 800-533-1710 to discuss the limitations of testing prior to sending a chorionic villus specimen for fragile X analysis.



Additional Testing Requirements


All prenatal specimens must be accompanied by a maternal blood specimen. Order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen. This must be a different order number than the prenatal specimen.



Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. For instructions for testing patients who have received a bone marrow transplant, call 800-533-1710.

 

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated

 

Prenatal Specimens

Due to its complexity, consultation with the laboratory is required for all prenatal testing; call 800-533-1710 to speak to a genetic counselor. 

 

Specimen Type: Amniotic fluid

Container/Tube: Amniotic fluid container

Specimen Volume: 20 mL

Specimen Stability Information: Refrigerated (preferred)/Ambient

Additional information:

1. A separate culture charge will be assessed under CULAF / Culture for Genetic Testing, Amniotic Fluid. An additional 2 to 3 weeks is required to culture amniotic fluid before genetic testing can occur.

2. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.

 

Specimen Type: Chorionic villi

Container/Tube: 15-mL tube containing 15 mL of transport media

Specimen Volume: 20 mg

Specimen Stability Information: Refrigerated

Additional Information:

1. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 2 to 3 weeks is required to culture chorionic villi before genetic testing can occur.

2. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.

 

Specimen Type: Confluent cultured cells

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks

Collection Instructions: Submit confluent cultured cells from another laboratory.

Specimen Stability Information: Ambient (preferred)/Refrigerated

Additional Information: All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.


Specimen Minimum Volume

Blood: 0.5 mL
Amniotic fluid: 10 mL
Chorionic villi: 5 mg

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reject Due To

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

Reference Values

Normal alleles: 5-44 CGG repeats

Intermediate (grey zone) alleles: 45-54 CGG repeats

Premutation alleles: 55-200 CGG repeats

Full mutation alleles: >200 CGG repeats

An interpretive report will be provided.

 

Methylation status:

Unmethylated: ≤20%

Partially methylated: 21-69%

Fully methylated: ≥70%

Day(s) Performed

Monday, Wednesday

Report Available

8 to 10 days

Specimen Retention Time

Whole Blood: 2 weeks (if available); Extracted DNA: 3 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81243

88233 (if appropriate)

88240 (if appropriate)

88235 (if appropriate)

81265 (if appropriate)

81244 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FXS Fragile X Syndrome, Mol. Analysis 81856-7

 

Result ID Test Result Name Result LOINC Value
52870 Result Summary 50397-9
52871 Result 81856-7
52872 Interpretation 69047-9
52873 Reason for Referral 42349-1
52874 Specimen 31208-2
52875 Source 31208-2
52876 Method 85069-3
52877 Released By 18771-6

Test Classification

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

Forms

1. 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:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Molecular Genetics: Congenital Inherited Diseases Patient Information (T521)

3. If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.

Secondary ID

35428