Label Specimens

In the clinical laboratory, the specimen label is the primary link between the biological sample and the patient’s identity. A failure in labeling is a critical pre-analytical error that can lead to misdiagnosis, mistreatment, or the rejection of irreplaceable specimens (e.g., amniotic fluid or bone marrow). Cytogenetics laboratories face unique challenges because specimens often undergo long-term culture (days to weeks) involving multiple vessel transfers

The Two-Identifier Rule

Regulatory standards (CLIA, CAP, TJC) mandate that every specimen container must be labeled with at least two unique patient identifiers at the time of collection and throughout all processing steps

• Acceptable Identifiers
  • Patient Name (First and Last)
  • Medical Record Number (MRN) or Hospital ID
  • Date of Birth (DOB)
  • Unique Laboratory Accession Number (assigned upon receipt)
• Unacceptable Identifiers
  • Bed number or Room number (patients move)
  • Diagnosis (e.g., “Leukemia patient”)
  • Physician name

The Chain of Custody (Traceability)

In cytogenetics, a single patient sample (primary tube) is split into multiple “daughter” vessels (flasks, tubes, slides). The identity must be maintained across every generation of the culture

• Primary Container: The original tube (e.g., Sodium Heparin green top) received from phlebotomy. Must have the original clinical label
• Culture Vessels (Flasks/Dishes): When setting up cultures, the laboratory scientist must label the T-25 flasks or Petri dishes before adding the specimen
  • Minimum Label: Lab Accession Number and Culture Type (e.g., “A” vs “B” culture)
• Harvest Tubes: When cells are transferred from flasks to centrifuge tubes for harvest, the label must be verified
• Slide Labeling
  • Slides are the permanent record. They must be labeled with the Accession Number, Slide Number, and Date
  • Etched/Printed Labels: Most labs use solvent-resistant printed labels or diamond-tip etching because slides are dipped in chemicals (xylene, methanol) that dissolve standard ink

Labeling Discrepancies (Rejection Criteria)

Upon receipt, the laboratory scientist must verify that the information on the tube matches the information on the requisition form exactly

• Major Discrepancy
  • Example: Name on tube is “Smith, John” but requisition says “Smith, Jane.”
  • Action: Rejection.: Do not process. In cytogenetics, where samples are often irreplaceable (bone marrow/amnio), the lab may attempt to “rescue” the specimen by requiring the collector to come to the lab and sign a Declaration of Correction or “Variance Form,” taking legal responsibility for the identity
• Minor Discrepancy
  • Example: Name is spelled “Jon” vs “John” but MRN and DOB match perfectly
  • Action: Process the sample but note the discrepancy in the LIS (Laboratory Information System) and correct the record
• Unlabeled Specimen
  • Action: Generally Rejected. “Irreplaceable” specimens may be processed but with a disclaimer in the final report stating the specimen was received unlabeled and identification was verified by the physician

Barcoding & LIS Integration

Modern laboratories utilize barcode systems to minimize human transcription errors

• Accessioning: The LIS generates a unique accession number (e.g., CYTO-23-1001) linked to the patient demographics
• Tracking: Barcodes are scanned at every step (Receipt \(\rightarrow\) Culture Setup \(\rightarrow\) Harvest \(\rightarrow\) Analysis). This creates an electronic audit trail of who handled the specimen and when
• Slide Scanning: Automated imaging systems (e.g., GenASIs) read the barcode on the slide to automatically link captured images to the correct patient folder in the database

Special Considerations for Cytogenetics

• Blind Studies: In some scenarios (proficiency testing or research), specimens are de-identified and labeled only with a randomization code to prevent bias
• Culture Failure: If a specific flask fails (e.g., contaminated), the label on that flask helps identify if the failure was random or linked to a specific lot of media used for that batch
• Aliquots: If a sample is shared with another department (e.g., Flow Cytometry), a secondary tube must be labeled with the full two identifiers before the sample is split