Chromosome Breakage Analysis (Sendout)

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General Information

Lab Name
Chromosome Breakage Analysis (Sendout)
Lab Code
RFACBA
Epic Ordering
Chromosome Breakage Analysis (Sendout)
External Test Id
6078
Description

Test Information: Chromosome breakage analysis is a test for assessing genomic instability. The most common syndrome for which this test is diagnostic is Fanconi anemia (FA). FA is characterized by bone marrow failure, increased risk for cancer, and physical abnormalities. Progressive bone marrow failure is responsible for the most significant morbidity and mortality. Clinically heterogeneous, FA individuals are at increased risk for acute myelogenous leukemia, myelodysplastic syndrome, and solid tumors of the neck, head, oral cavities, and genitourinary system. Congenital abnormalities are present in approximately 70% of FA patients and include: café au lait spots or hypopigmentation; short stature; radial ray defects; eye defects such as microphthalmia; malformations of the kidney, genitalia, heart, gastrointestinal tract, ears, and feet. Currently, 21 genes have been identified that, when mutated, can cause FA or an FA-like phenotype.

The first step in FA diagnosis is to perform a breakage analysis on peripheral blood. However, some FA patients undergo a self-correction of cells in the hematopoietic lineage, resulting in a normal blood breakage study. In such a case, breakage analysis of skin fibroblasts is necessary to detect the increased breakage and radial formation. This phenomenon is known as somatic mosaicism. Fibroblast breakage studies may also be preferable for patients with very low white blood cell counts.

Ordering Requirements:

  • For orders placed in Epic using the RFACBA test code, a separate OHSU requisition is not required. If known, the most recent WBC count and lymphocyte percentage should be included for proper test interpretation.
  • Laboratory Medicine Resident (LMR) approval is required for orders placed as LABUND (Laboratory Undefined). Direct Epic ordering is limited to FHCC locations only.

Collection Note: Limited sample stability. Specimens must arrive must arrive at OHSU Knight Diagnostic Labs within 24 hours of collection. Failure to follow collection guidelines may result in cancellation.

Forms & Requisitions
Synonyms
6078, DNA Repair Defect, FA, Fanconi's Anemia, Fragility Test
Components

Interpretation

Method

Cells are cultured in the presence of the clastogens mitomycin C (MMC) and diepoxybutane (DEB). Metaphase chromosomes are prepared from each culture and stained with Wright stain. Fifty metaphases are scored from each culture for the presence of breaks and radial formations.

Reference Range
See individual components
Ref. Range Notes

An interpretive report will be provided.

Ordering & Collection

Specimen Type
Blood
Collection

Collection Timing:

  • Specimen must be drawn Monday - Friday only, between 10:00 am and 1:30 pm (noon if drawn offsite), and received at the UW-MT Lab by 2pm for same-day shipment to OHSU. Do not collect on or before holidays.
  • FHCC: For patients collected at a Fred Hutch location, the sample must be received in the SLU Alliance Lab prior to 12:00 pm. At South Lake Union, schedule blood draw appointment prior to 11:00 am. Collection at Fred Hutch Community Sites is not recommended.

Sample Requirements: Blood

  • Collect 5-10 mL blood in GREEN TOP SODIUM HEPARIN tube (see exception below)
    • Note: When WBC count is less than 2000 or lymphocyte count is less than normal, 10 mL of sodium heparinized blood is required. When WBC and lymphocyte counts are extremely low (<100), 20-30 mL of blood is considered optimal.
    • If Epic order indicates: "Patient has a very low white blood count or lymphocyte count - YES. ADDITIONAL BLOOD IS REQUIRED," draw 30 mL of NaHep blood. Additional CID labels will not print in Sunquest, so labels may need to be reprinted.
  • Unacceptable: Any other tube type, including lithium heparin.

Sample Requirements: Skin Chromosome Study

  • 3 cubic mm skin or other tissue in Cytogenetics Tissue Transport Medium, sterile Ringer's solution, or in sterile normal saline.
  • Store at ambient temperature and ship the same day of collection.
Forms & Requisitions
Approval Required
LMR approval required for orders placed as LABUND.
Handling Instructions

Outside Laboratories: Due to limited sample stability, this test is offered to patients within the UW Medicine system only. Outside clients should arrange for testing directly with Knight Diagnostic Laboratories.

Quantity
requested: 10 mL NaHep whole blood if normal WBC and lymphocyte count (see Collection information for exceptions)
minimum: 5 mL NaHep whole blood if normal WBC and lymphocyte count (see Collection Information for exceptions)

Processing

Processing

Store and transport sample(s) at room temperature and notify Sendouts immediately upon receipt. Expedited processing is required.

FHCC SPS: Orders must arrive at UW-MT SPS by 2 p.m. for same-day shipment. Send sample(s) immediately via Delivery Express courier and notify Sendouts.

Sendouts:

  • Order OHSU Test:
    • Blood: 6078 (Breakage Analysis: Blood Chromosome Study).
    • Fibroblasts or Skin Tissue: 6080 (Breakage Analysis: Skin Chromosome Study)
  • Complete the patient demographic and sample collection information on the OHSU requisition. Print the Epic requisition that contains additional provider and clinical information. Include both requisitions with the sample.
    • Note: The OHSU requisition is required. Do not send samples with only an Epic requisition.
  • Ship samples at ambient temperature the same day of collection, specifying FedEx First Overnight shipping.
  • If shipping samples on a Friday, select FedEx First Overnight and Saturday Delivery. Contact Knight Diagnostic Laboratories at (855) 535-1522 to notify them of the incoming specimen and provide patient and FedEx tracking information.

Stability: Ambient (Critical): 24 hours, Refrigerated: Unacceptable; Frozen: Unacceptable.

Performance

LIS Dept Code
Sendouts (SO)
Performing Location(s)
Sendout Oregon Health Sciences University, Molecular Diagnostics Center, Knight Diagnostic Laboratories
855-535-1522

2525 SW 3rd Ave
Suite 350
Portland, OR 97201
Frequency
Performed: Mon - Sat. TAT: 7 - 10 days.
Available STAT?
No

Billing & Coding

CPT codes
LOINC
30896-5