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Test ID XHIM X-Linked Hyper IgM Syndrome, Blood

Useful For

Screening for X-linked hyper-IgM (XL-HIGM) or CD40L deficiency, primarily in male patients younger than 10 years of age


Ascertaining XL-HIGM carrier status in women of child-bearing age (younger than 45 years old)

Genetics Test Information

CD40LG is located on the long arm of the X-chromosome (Xq 21.3-22) and encodes the surface protein CD40 ligand (CD154). It is critical for the formation of germinal centers and, therefore, class switch recombination and somatic hypermutation. More than 100 unique genetic variants of CD40LG have been described. The observed variants are scattered throughout the gene but are more prevalent in exon 5.

Method Name

Flow Cytometry

Reporting Name

X-Linked Hyper IgM Syndrome, B

Specimen Type

WB Sodium Heparin

Shipping Instructions

Specimens are required to be received in the laboratory weekdays and by 4 p.m. on Friday. Collect and package specimen as close to shipping time as possible.


It is recommended that specimens arrive within 24 hours of collection.


Specimens arriving on the weekend and observed holidays may be canceled.


Specimens received more than 72 hours after collection will be rejected and the assay will not be performed.

Necessary Information

Ordering physician's name and phone number are required.

Specimen Required

Container/Tube: Green top (sodium heparin)

Specimen Volume: 4 mL

Collection Instructions: Send specimen in original tube. Do not aliquot.

Additional Information: For serial monitoring, it is recommended that specimen collection be performed at the same time of day.

Specimen Minimum Volume

1.2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
WB Sodium Heparin Ambient 72 hours GREEN TOP/HEP

Reference Values


Day(s) Performed

Monday through Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

88184-Flow cytometry, cell surface, cytoplasmic

88185 x 6-Each additional marker

LOINC Code Information

Test ID Test Order Name Order LOINC Value
XHIM X-Linked Hyper IgM Syndrome, B 98239-7


Result ID Test Result Name Result LOINC Value
82964 CD40 Ligand Expression 98240-5
29040 CD40muIg (Function) 98241-3
23901 Interpretation 69052-9

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were 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.

Report Available

3 to 4 days

NY State Approved