UBA1 Mutation Quantitative Detection, ddPCR (Sendout)

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General Information

Lab Name
UBA1 Mutation Quantitative Detection, ddPCR (Sendout)
Lab Code
RUBA1Q
External Test Id
UBA1Q
Description

Useful For: Monitoring patients with known pathogenic variant(s) in the UBA1 gene and a diagnosis of VEXAS syndrome. UW OncoPlex Single Gene [OPG] is the recommended first-line test for patients presenting with symptoms concerning for or consistent with VEXAS syndrome.

Genetics Test Information: A highly sensitive quantitative assay for the detection of 7 UBA1 mutations (c.122T>C, p.Met41Thr; c.121A>G, p.Met41Val; c.121A>C, p.Met41Leu; c.118-1G>C, p.?; c.118-2A>C, p.?; c.118-9_118-2del, p.?; and c.167C>T, p.Ser56Phe).

Highlights: This test sensitively and specifically detects seven of the most common recurrent somatic mutations in the UBA1 gene. UBA1 mutations are responsible for VEXAS (vacuoles, E1-enzyme, X-linked, autoinflammatory, somatic) syndrome, which is a variably aggressive inflammatory condition. VEXAS syndrome patients also often present with blood count and bone marrow abnormalities that can be associated with the presence of myelodysplastic syndrome or other hematologic neoplasms. Detection of UBA1 mutation is critical for diagnosing VEXAS syndrome. This droplet digital polymerase chain reaction assay offers improved analytical sensitivity over other commonly used test methodologies.

Ordering Requirements:

  • This test is pre-approved for FHCC Hematology Clinics. Orders from other locations require approval from the Laboratory Medicine Resident on-call.
  • A completed Mayo Hematopathology Patient Information Form is required. Forms may be uploaded to Epic Media (recommended) or accompany the sample to the lab.
References
Synonyms
Acquired bone marrow failure, Clonal hematopoiesis, Macrocytic anemia, Periorbital edema, Sweet's syndrome, Systemic inflammation, UBA1Q, Vacuolated bone marrow cells, VEXAS (Vacuoles E1-enzyme X-linked Autoinflammatory Somatic) syndrome, VEXAS Syndrome
Components
Code Name
RUBA1S UBA1 Mutation Quantitative ddPCR, Specimen Type
RUBA1R UBA1 Mutation Quantitative ddPCR, Result
RUBA1I UBA1 Mutation Quantitative ddPCR, Interpretation
RUBA1P UBA1 Mutation Quantitative ddPCR, Signing Pathologist

Interpretation

Method

Droplet Digital Polymerase Chain Reaction

Reference Range
See individual components
Ref. Range Notes

An interpretive report will be provided.

Interferences and Limitations

Cautions: Other potential UBA1 variants outside the 7 assay targets are not detected by this assay. The absence of UBA1 mutation does not exclude other causes of inflammatory disorders or clonal myeloid processes. Although most patients with VEXAS syndrome have high UBA1 mutation variant fractions, this assay may not identify very low mutation burden cases below the limit of detection.

Ordering & Collection

Specimen Type
Blood, Bone Marrow
Collection

Blood: 4 mL blood in LAVENDER TOP (EDTA) tube

Bone Marrow: 2 mL bone marrow aspirate in LAVENDER TOP (EDTA) tube

  • Also Accepted (WB or BM): Yellow (ACD-B) or green top (heparin) tube

Extracted DNA: At least 50 mcL DNA at a concentration of 50 ng/mcL in a 1.5 to 2 mL tube. Write the volume and concentration of DNA on the sample label.

Forms & Requisitions
Approval Required
Pre-approved for FHCC Hematology Clinics. Orders from other locations require approval from the Laboratory Medicine Resident on-call.
Handling Instructions

Outside Laboratories: Refrigerate whole blood or bone marrow aspirate while awaiting shipment. Expedite transport to the lab; specimens must be received at Mayo within 7 days of collection (account for one day of transport from UW-Montlake to Mayo). Transport sample with a cold pack.

Stability: Refrigerated (preferred): 7 days; Ambient: 7 days; Frozen: Unacceptable.

Reject Due To: Gross hemolysis; moderately to severely clotted specimen.

Quantity
Requested: 4 mL EDTA whole blood or 2 mL bone marrow
Minimum: 4 mL EDTA whole blood or 2 mL bone marrow

Processing

Receiving Instructions

Blood/Bone Marrow: Refrigerate whole blood or bone marrow aspirate.

Extracted DNA: Freeze or refrigerate sample.

Result-at-Entry:

  • RUBA1S (Specimen Type): <Enter the the appropriate specimen type code from the table below.>

Specimen Type Codes:

ETC Translation
WB Whole Blood
BNM Bone Marrow
DNAEXT Extracted DNA

Sendouts:

  • Order Mayo Test: UBA1Q
  • Interfaced: Yes [Interface: 601; Worksheet: MARF]
  • Samples must be received by Mayo within 7 days of collection.

Stability (Blood/Bone Marrow): Refrigerated (preferred): 7 days; Ambient: 7 days; Frozen: Unacceptable.

Stability (DNA): Frozen: Preferred; Refrigerated: Acceptable.

Reject Due To: Gross hemolysis; moderately to severely clotted specimen.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (RF)(MARF)
Frequency
Performed: Monday through Saturday. Report Available: 4-8 days from sample receipt at Mayo Clinic Labs.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
81403
Interfaced Order Code
UOW6494