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HelpTest Code XHIM X-Linked Hyper IgM Syndrome, Blood
Reporting Name
X-Linked Hyper IgM Syndrome, BPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Screening for X-linked hyper-IgM (XL-HIGM) or CD40L deficiency, primarily in male patients younger than 10 years
Ascertaining XL-HIGM carrier status in women of child-bearing age (younger than 45 years)
Method Name
Flow Cytometry
Shipping Instructions
Testing performed Monday through Friday. Specimens not received by 4 p.m. Central time on Fridays may be canceled.
Specimens arriving on the weekend and observed holidays may be canceled.
Collect and package specimen as close to shipping time as possible. It is recommended that specimens arrive within 24 hours of collection.
Necessary Information
The ordering healthcare professional's name and phone number are required.
Specimen Required
Container/Tube: Green top (sodium heparin)
Specimen Volume: 4 mL
Collection Instructions: Send whole blood 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 Type
WB Sodium HeparinSpecimen Minimum Volume
1.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| WB Sodium Heparin | Ambient | 72 hours | GREEN TOP/HEP |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Reference Values
Present
Interpretation
This is a qualitative assay; CD40L-protein expression and function are reported as present or absent. Absence of CD40L-protein expression and function is consistent with X-linked hyper-IgM (XL-HIGM). In female patients, the presence of 2 populations-normal and abnormal-is consistent with carrier status.
Most patients (80%-90%) with XL-HIGM have absent or significantly reduced CD40L expression on their activated CD4 T cells. Patients with normal CD40L expression, but abnormal function, show an absence of binding with soluble chimeric CD40-uIg antibody, substantiating a diagnosis of XL-HIGM. Female patients who are carriers for this disease will show a typical bimodal pattern of CD40L expression, with 50% of the T cells lacking any CD40L expression. In the case of aberrant protein function, a similar profile will be obtained with the CD40-uIg antibody.
CD69 is a marker for T-cell activation and serves as a positive control; in the absence of induced CD69 expression on T cells, the presence of XL-HIGM cannot be assessed.
Day(s) Performed
Monday through Friday
Report Available
3 to 4 daysTest 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.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 |