Ordering Recommendation

Screening test for Lynch syndrome. Use to determine potential eligibility for immunotherapy by identifying microsatellite instability-high (MSI-H) cancers.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Tumor AND normal epithelial tissue.

Specimen Preparation

Tissue: Formalin fix (10 percent neutral buffered formalin) and paraffin embed tissue. Protect from excessive heat. Transport tissue block(s) or 10 unstained 5-micron slides (5 tumor and 5 normal epithelial). Transport block(s) and/or slide(s) in a tissue transport kit (ARUP Supply #47808) available online through eSupply using ARUP Connect  or contact ARUP Client Services at 800-522-2787.

Storage/Transport Temperature

Room temperature. Also acceptable: Refrigerated. Ship in cooled container during summer months

Unacceptable Conditions

Less than 25 percent tumor or less than 50 percent normal epithelial tissue. Specimens fixed/processed in alternative fixatives (alcohol, Prefer) or heavy metal fixatives (B-4 or B-5). Decalcified specimens.


Include surgical pathology report.
If multiple specimens (blocks or slides) are sent to ARUP, they must be accompanied by one of the following: an order comment indicating that the ARUP pathologist should choose the specimen most appropriate for testing (e.g., "Choose best block"), or individual orders for each sample submitted. A Pathologist Block Selection Fee (ARUP test code 3002076) will be added to orders that utilize the first option. If multiple specimens are sent to ARUP without a request for pathologist block/slide selection or individual orders, they will be held until clarification is provided.


Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable


Capillary Electrophoresis/Polymerase Chain Reaction (PCR)




10-20 days

Reference Interval

Interpretive Data

Refer to report.

Compliance Category

Laboratory Developed Test (LDT)


Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0051741 Microsatellite Marker BAT-25 81697-5
0051742 Microsatellite Marker BAT-26 81698-3
0051743 Microsatellite Marker MONO-27 81701-5
0051744 Microsatellite Interpretation 43368-0
0051745 Microsatellite Marker NR-21 81699-1
0051746 Microsatellite Marker NR-24 81700-7
2001370 Microsatellite Instability Specimen 31208-2
2002148 Block ID 57723-9
* 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.


  • BAT -25, BAT-26, MON-27, NR-21, NR-24 genotypes
  • HNPCC tumor screening
  • Lynch Syndrome MSI
  • Lynch syndrome tumor screening
  • microsatellite instability
  • MSI
  • MSI Lynch syndrome
Microsatellite Instability (MSI) HNPCC/Lynch Syndrome by PCR