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Test Code XAMERK Anti Merkel Cell Panel

Clinical Information

SmT oncoprotein antibodies are present in the blood of 50% of patients when they have clinically detectable Merkel Cell Carcinoma (MCC). In patients who make oncoprotein antibodies, titers are expected to decrease significantly within 3 months of successful treatment of MCC. Changes in oncoprotein titers of less than 25% may not be biologically significant. A significant rise in titer or stabilization above 2000STU may be associated with persistent or recurrent MCC. 

Synonym

  • XAMERK
  • AMEKR2, MCC
  • MCPyV
  • Merkel cell carcinoma
  • Polyomavirus oncoprotein antibodies
  • Polyomavirus VP1 capsid antibody
  • Small T antibodies 

Profile Information

All samples include testing for antibodies to the Merkel Cell Carcinoma (MCC) oncoprotein.

Specimen Required

6 mL blood in Red Top or Gold SST. Centrifuge and separate serum within 4 hours of collection. 2 ml of serum required. 

Specimen Stability Information

Refrigerated (preferred): 7 days                      
Frozen at -20 degrees: Long term

Rejected Due To

  • Specimens other than serum 

Forms

AMERK Requisition

Reflex Tests

In addition, screening for the Merkel Cell polyomavirus VP1 capsid antibody is done once, on the first sample ordered for AMERK testing (AMERK2) and billed separately. The VP1 capsid antibody test is reflexively added to the order by the laboratory.

Reference Values

See Report

Interpretation

Screening for the Merkel cell polyomavirus VP1 capsid antibody is done once, on the first sample ordered for AMERK testing (and billed separately). This assay is used to screen Merkel Cell Carcinoma (MCC) patients for current or prior infection with the Merkel cell polyomavirus. Patients who lack these antibodies should not be monitored with additional AMERK testing because they do not make antibodies to the viral oncoprotein and should be monitored by other means. VP1 capsid antibodies are not an indicator of disease activity.

Method Description

Laboratory developed Luminex paramagnetic bead, multiplex assay

Performing Lab

University of Washington 

Day(s) Performed

Set up on Mondays

Report Available

4 weeks

CPT Code Information

0058U

AMERK2: 0059U

LOINC Code Information

18727-8