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Hematology

Regulation

The operation of a clinical hematology laboratory is strictly governed by federal regulations and accreditation standards designed to ensure the highest level of patient safety. In the United States, the overarching law is the Clinical Laboratory Improvement Amendments of 1988 (CLIA’88). While CLIA sets the minimum federal standards, many laboratories subscribe to “deemed status” accrediting agencies, such as the College of American Pathologists (CAP) or The Joint Commission (TJC), which enforce standards that are equal to or more stringent than CLIA. An entry-level laboratory scientist must understand the three pillars of regulatory compliance: Proficiency Testing, Competency Assessment, and Accreditation Standards

Proficiency Testing (PT)

Proficiency Testing, also known as External Quality Assessment (EQA), is a federal requirement for all non-waived testing. It is the process by which a laboratory’s accuracy is verified by an outside agency. Failure to perform PT successfully can result in sanctions, including the suspension of the laboratory’s ability to perform specific tests

The PT Process

  • Sample Receipt: The laboratory receives “blind” samples (usually 5 samples per “event,” 3 times per year) from a provider like CAP. These samples mimic patient blood but have known values established by peer groups
  • Testing Protocol: PT samples must be tested in the same manner as patient samples. They must be integrated into the regular workflow and tested by the personnel who typically run patient testing, using the primary instrument
  • Strict Prohibitions
    • Inter-laboratory Communication: It is strictly prohibited to discuss PT samples or results with another laboratory before the submission deadline. Doing so is considered “collusion” and can result in the loss of the laboratory’s CLIA license and the prohibition of the laboratory director from directing a lab for two years
    • Referral: You cannot send a PT sample to a reference lab (even if you would normally send a patient sample there for confirmation). This constitutes a “PT Referral” violation
  • No Special Treatment: Laboratories cannot perform valid duplicate testing on PT samples unless it is standard procedure to run every patient sample in duplicate (which is rare in Hematology)

Evaluation & Scoring

  • Peer Group Grading: Results are compared to a “peer group” consisting of other laboratories using the same instrument and reagent system. Performance is measured using the Standard Deviation Index (SDI). An SDI greater than 2.0 indicates the result is outside the consensus mean
  • Passing Score: For most hematology analytes, a score of 80% is required to pass an event (4 out of 5 samples must be correct). “Correct” is usually defined as the target value ± a fixed percentage or fixed amount (e.g., Target ± 6% for Hemoglobin)
  • Unsatisfactory Performance: Failure to achieve a passing score in a single event
  • Unsuccessful Performance: Failure to achieve a passing score in two out of three consecutive events. This triggers serious regulatory action, often requiring a “Cease Testing” order for the failed analyte until remediation is proven and reinstatement is granted by the inspecting agency

Regulated Analytes vs. Non-Regulated Analytes

  • Regulated Analytes: Tests specifically listed by CLIA (e.g., RBC, WBC, Plt, Hgb, Hct, Prothrombin Time) require formal PT enrollment
  • Non-Regulated Analytes: For tests not specifically listed (e.g., Reticulocytes in some contexts, or specialized coagulation factors), the laboratory is still required to verify accuracy twice a year. This can be done via alternative assessments, such as “split-sample” testing with a reference laboratory

Competency Assessment

Competency assessment is distinct from training. While training involves teaching an employee a new skill, competency assessment verifies that the employee has retained that skill and applies it correctly over time. CLIA mandates specific intervals and methods for this assessment

Timing of Assessment

  • Semiannual: New employees must be assessed at the 6-month mark during their first year of employment
  • Annual: After the first year, competency must be assessed annually for all testing personnel
  • Remedial: If an employee fails a competency assessment or a specific method fails QC repeatedly due to operator error, retraining and re-assessment must occur immediately

The Six Elements of Competency

CLIA mandates that the following six specific elements must be assessed for each test system (e.g., The Automated CBC, The Manual Differential, The Coagulation Analyzer). It is a common exam topic to identify which of these are required

  • Direct Observation of Test Performance: Watching the laboratory scientist perform the routine testing workflow
  • Direct Observation of Instrument Maintenance/Function Checks: Watching the laboratory scientist perform daily, weekly, or monthly maintenance
  • Monitoring Recording and Reporting: Reviewing worksheets or LIS logs to ensure results are entered and reported correctly (including critical value documentation)
  • Review of Work Records: Checking QC logs, PT results, and preventative maintenance records performed by the employee
  • Assessment of Problem Solving: Giving the laboratory scientist a written scenario or a “dummy” sample with a known error (e.g., a short sample) to see if they follow the correct troubleshooting steps
  • Assessment of Specimen Handling: Verifying the employee knows rejection criteria (e.g., clotted samples, hemolysis) and processing requirements

Accreditation Standards & Documentation

Accreditation agencies like CAP provide detailed “checklists” that translate CLIA laws into actionable laboratory requirements. The Hematology laboratory must be inspection-ready at all times

Method Validation & Verification

Before a new hematology analyzer is put into use, it must undergo rigorous testing to prove it performs as claimed by the manufacturer. This data is reviewed during inspections

  • Accuracy: Comparing results from the new instrument to the old instrument or a reference method
  • Precision: Running the same sample multiple times to ensure reproducibility
  • Reportable Range (Linearity): Verifying the highest and lowest values the instrument can accurately measure without dilution
  • Reference Intervals: Verifying that the “normal ranges” provided by the manufacturer are appropriate for the specific patient population served by the laboratory

Document Control

  • Standard Operating Procedures (SOPs): Every test must have a written procedure. These must be reviewed and signed by the Medical Director (Pathologist) annually (or every two years depending on the agency, though CLIA requires reviewing new changes). Staff must read and sign these upon hire and upon any revision
  • Record Retention: Laboratories must store records for specific timeframes for regulatory review
    • General Lab Records (QC, Requisitions, Reports): 2 years
    • Blood Bank: 5 to 10 years (or indefinite for donor records)
    • Pathology/Cytology Slides: 10 years (Hematology smears are usually kept for 7 days unless they are part of a permanent pathology record, though proficiency testing slides must be kept for 2 years)

Personnel Standards

CLIA categorizes tests by complexity: Waived, Moderate Complexity, and High Complexity. Most automated hematology is Moderate or High; Manual Differentials are High Complexity

  • Testing Personnel: Must have at least an associate degree (MLT) for high complexity testing, though many institutions require a bachelor’s degree (MLS). They are responsible for following procedures and performing QC
  • Technical Consultant/Supervisor: Must be available to provide technical oversight, resolve technical problems, and perform competency assessments. Requirements usually involve a bachelor’s degree and specific experience years
  • Clinical Consultant: Usually a physician (Pathologist/Hematologist) who communicates with clinicians regarding the medical significance of laboratory data