Ordering Recommendation

Use to assess for the presence of TPSAB1 copy number variants. Consider in individuals with confirmed or suspected systemic mastocytosis or mast cell activation syndrome. TPSAB1 variants may also be associated with serum tryptase at or above 8 ng/mL, severe allergic reactions, recurrent anaphylaxis, skin flushing and pruritis, itching, Ehlers-Danlos syndrome or other connective tissue abnormalities, severe postural orthostatic tachycardia syndrome or other systemic venom reactions, gastroparesis, irritable bowel syndrome, dysautonomia, sleep disruption, and other systemic immediate hypersensitivity reactions. 

New York DOH Approval Status

This test is not New York state approved. There are no New York state-approved laboratories available. Submit a Non-Permitted Laboratory Request Form (NPL) to the NYDOH prior to collection of specimen. If NPL is approved by NYDOH, and sample is received at ARUP, testing will be performed.

Specimen Required

Patient Preparation

Whole blood or bone marrow in lavender (EDTA) preferred. Also acceptable: Green (sodium heparin)

Specimen Preparation

Whole Blood: Do not freeze. Transport 5 mL whole blood. (Min: 1 mL)
Bone Marrow: Do not freeze. Transport 3 mL bone marrow. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Plasma, serum, FFPE tissue blocks/slides, or fresh or frozen tissue. Specimens collected in anticoagulants other than EDTA (purple) or sodium heparin (green). Clotted or grossly hemolyzed specimens.


Refrigerated: 7 days; Frozen: Unacceptable


Droplet Digital PCR (ddPCR)




10-14 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
3017400 TPSAB1, Source 31208-2
3017401 Alpha-tryptase Copy Number 82155-3
3017402 Beta-tryptase Copy Number 82155-3
3017403 TPSAB1 Interp 101397-8
* 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.


  • Autosomal dominant
  • Copy number variation (CNV)
  • Cutaneous mastocytosis (CM)
  • Hereditary alpha tryptasemia (HaT)
  • Hypertryptasemia
  • Idiopathic MCAS
  • Mast cell activation syndrome (MCAS)
  • Mast cell disorders
  • Recurrent anaphylaxis
  • Secondary MCAS
  • Systemic mastocytosis (SM)
  • Tryptase alpha-1/beta-1 (TPSAB1)
TPSAB1 Copy Number Analysis by ddPCR