Ordering Recommendation

Preferred test to diagnose fragile X syndrome. May be used as carrier screening in individuals with a positive family history.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Lavender (K2EDTA), pink (K2EDTA), or yellow (ACD solution A or B)

Specimen Preparation

Transport 2 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated. Also acceptable: Ambient.

Unacceptable Conditions

Room temperature: 1 week; Refrigerated: 1 month; Frozen: Unacceptable


Polymerase Chain Reaction (PCR)/Capillary Electrophoresis




4-14 days

Reference Interval

By report

Interpretive Data

Refer to report.

Compliance Category

Laboratory Developed Test (LDT)


If a CGG repeat of 100 or greater is detected by PCR and capillary electrophoresis, methylation analysis will be added. Additional charges apply.

Hotline History


CPT Codes

81243; if reflexed, add 81244


Component Test Code* Component Chart Name LOINC
0050556 Fragile X Allele 1 45321-7
0050558 Fragile X Allele 2 45322-5
0050559 Fragile X Methylation Pattern 41107-4
0050579 Fragile X Interpretation 36913-2
2001310 FRAG X Specimen 66746-9
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Inherited Mental Retardation (Fragile X (FMR1) Diagnostic)
  • Martin-Bell Syndrome (Fragile X (FMR1) Diagnostic)
Fragile X (FMR1) with Reflex to Methylation Analysis