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(TM) 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 in any fixative other than 10 percent neutral buffered formalin.
Bone specimens submitted in non-EDTA decalcifier.


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