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Cytogenetics

Retention Times

Cytogenetics laboratories must adhere to strict retention schedules mandated by federal law (CLIA’88), accrediting bodies (CAP, TJC), and state regulations (which may be stricter, e.g., New York State). These rules ensure that materials are available for re-testing, legal review, or longitudinal patient care

Specimen & Sample Retention

  • Original Specimen (Primary Tube)
    • Requirement: Typically 7 days (Blood) to 2 weeks (Amnio) after report release
    • Purpose: To allow for re-initiation of culture if the first attempt fails or if additional testing (e.g., Microarray) is ordered reflexively
  • Cell Pellets (Fixed Suspensions)
    • Requirement
      • Constitutional: Variable, but often 2 weeks post-report
      • Oncology (Leukemia): Indefinite (or >10 years) is best practice, though regulations may only require 2 years
    • Purpose: Fixed pellets are stable for decades at \(-20^{\circ}\text{C}\). They serve as a “biobank” for the patient. If the patient relapses in 5 years, the old pellet can be pulled to check the original clone’s genetics using new FISH probes
  • DNA (Extracted)
    • Requirement: Often 2 years or longer (Molecular Genetics rules)

Slide Retention

  • Routine Analysis Slides (G-banded)
    • Requirement: 3 Years (CAP/CLIA)
    • Reason: Slides are the primary evidence of the microscopic analysis. They must be available for audit or re-review
  • FISH Slides
    • Requirement: Technically only required to be kept for 24 hours if digital images are kept. If no images are taken, slides must be kept, but fluorescence fades rapidly (weeks), rendering them useless. Therefore, digital archiving is the standard
  • Broken/Permanently Mounted Slides
    • If a slide is used for the final karyotype, it is often kept indefinitely by the lab as a teaching or reference file, although 3 years is the legal minimum

Records & Reports (Paper/Digital)

  • Final Report
    • Requirement: 10 Years (CAP) to 20+ Years (some states/hospital policies)
    • Note: The final report is part of the medical record and is often kept indefinitely in the Electronic Medical Record (EMR)
  • Worksheets/Raw Data
    • Requirement: 2 Years
    • This includes the tech’s bench notes, cell coordinates, and count sheets
  • Instrument Printouts
    • Requirement: 2 Years
    • Example: Maintenance logs, temperature charts

4. Image Retention

  • Digital Images (Karyograms & FISH)
    • Requirement: 10 Years (CAP)
    • Because glass slides break and stain fades, the Digital Image: is considered the permanent surrogate for the specimen
    • Constitutional/Pediatric: Many labs keep these 21 years: (until the child reaches adulthood) due to liability statutes regarding birth defects

Summary Table of Minimum Retention (CLIA/CAP)

Item Minimum Retention Recommended/Best Practice
Wet Specimen 1 week post-report 2 weeks
Fixed Pellet 2 weeks Indefinite (Oncology)
Slides 3 years Indefinite (Abnormals)
Digital Images 10 years 20 years
Final Report 10 years Indefinite
QC Records 2 years 2 years
Proficiency Testing 2 years 2 years

Note: Always follow the strictest: regulation applicable to your specific location (e.g., State Law > Federal Law).