LAB QA

02. Laboratory QA Framework

A. Pre-Analytical Phase (Before the test is run)

Most laboratory errors (approx. 70%) occur in this phase.

1. Sample Rejection Rate:

   • Indicator: % of samples rejected due to non-conformity.

   • Reasons to track: Hemolysis (blood breakdown), Clotted sample (EDTA), Insufficient volume (QNS), Wrong container, Wrong label.

   • Target: < 1-2%.

2. Patient Identification Error Rate:

   • Indicator: Number of samples received with mismatched request forms vs. sample labels.

3. Phlebitis/Hematoma Rate (Phlebotomy QA):

   • Indicator: Incidence of patient injury during blood collection (OPD Collection Centre).

4. Order Entry Error Rate:

   • Indicator: Discrepancies between what the doctor ordered and what was entered into the LIS (Lab Information System).

5. Transport Time compliance:

   • Indicator: Time from "Sample Collection" in ward to "Accession/Receipt" in Lab. Critical for ABG (Arterial Blood Gas) and CSF samples.

B. Analytical Phase (During the testing)

Focuses on accuracy, precision, and equipment health.

1. Internal Quality Control (IQC) Compliance:

   • Indicator: % of tests where IQC (High/Normal/Low controls) was run and was within limits (Westgard Rules) before patient samples were tested.

2. External Quality Assurance (EQAS/PT) Performance:

   • Indicator: Z-Score performance in Inter-laboratory comparisons (e.g., AIIMS EQAS, CMC Vellore EQAS, Bio-Rad).

   • Target: Z-Score between -2 and +2.

3. Equipment Downtime Rate:

   • Indicator: % of hours analyzers are out of order. (High downtime impacts hospital TAT).

4. Reagent Utilization & Expiry:

   • Audit: Zero incidents of using expired reagents.

5. CV% (Coefficient of Variation):

   • Indicator: Measures precision (reproducibility) of the tests over a month.

C. Post-Analytical Phase (Reporting)

Focuses on speed and communication.

1. Turnaround Time (TAT) Compliance:

   • Indicator: % of reports released within the defined time limit.

   • Categories:

     • STAT/Critical (ER/ICU): < 45-60 mins.

     • Routine In-patient: < 4-6 hours.

     • Specialized (Hormones/Tumor markers): Defined schedule (e.g., weekly).

2. Critical Alert Reporting Rate:

   • Indicator: % of critical values (e.g., Potassium > 6.0, Hemoglobin < 5.0, Troponin +ve) communicated to the clinician within 15-30 minutes of result generation.

   • Audit: Check the "Critical Value Register" for: Who was called, Time called, and Name of receiver.

3. Amended Report Rate:

   • Indicator: Number of reports recalled/corrected after being released to the patient. (Indicates severe error).

4. Auto-Validation Failure Rate:

   • Indicator: If LIS auto-validates normal results, how many needed manual intervention due to error flags.

D. Specific QA for Sub-Departments (Medical College Context)

1. Histopathology & Cytology:

• Frozen Section vs. Paraffin Section Correlation:

  • Indicator: % of cases where the rapid intra-operative diagnosis matched the final biopsy report.

• Cyto-Histo Correlation:

  • Indicator: % of cases where FNAC/Pap smear findings matched the final tissue biopsy.

• Block/Slide Quality Index:

  • Audit: Score for staining quality, section thickness, and coverslipping.

• TAT for Biopsy: Standard (e.g., 3-5 days) vs. Complex (requiring IHC).

2. Microbiology:

• Blood Culture Contamination Rate:

  • Indicator: % of blood cultures growing skin commensals (e.g., CoNS or Diphtheroids) instead of pathogens. (Target: < 3%).

• Gram Stain vs. Culture Correlation:

  • Indicator: Consistency between preliminary Gram stain report and final culture growth.

• Antibiogram Generation:

  • QA: Annual publication of hospital-specific antibiograms to guide empirical antibiotic therapy.

E. Biosafety & Infection Control

1. Staff Vaccination Status:

   • Audit: 100% Hepatitis B vaccination (with Anti-HBs titer check) for all lab technicians.

2. Spill Management Compliance:

   • Drill: Response time and technique for cleaning Biological Spills (Mercury/Blood/Acid).

3. Biomedical Waste Handling:

   • Audit: Proper disposal of samples (autoclaving cultures before disposal).

F. Academic & Managerial QA

1. Validation of Reference Ranges (Biological Reference Interval):

   • Audit: Verification of normal ranges specifically for the local population (once a year or when changing machines).

2. Stockout Incidents:

   • Indicator: Number of times tests were stopped due to unavailability of reagents/kits.

3. Inter-Observer Variability (Pathology):

   • Academic Audit: Random slide review by two different faculty members to check for diagnostic agreement.

4. Referral Lab Monitoring:

   • Audit: If tests are outsourced, checking the accreditation status and QA reports of the tie-up lab.

Implementation Checklist for Lab Director/Manager

• Daily:

  • Temperature Log: Refrigerator (2-8°C) and Freezer (-20°C) charts.
    IQC Review: Review Levey-Jennings charts before authorizing resident/staff to run patient samples.
    Critical Value Logbook: Sign-off on previous day's critical calls.

• Monthly:

  • TAT Analysis: Identify outliers (e.g., Why was Troponin delayed on the 15th?).
    Sample Rejection Analysis: Identify which ward/nurse is sending the most hemolyzed samples (Training need).
    Pipette Calibration: Check accuracy of pipettes.

• Bi-Annually/Annually:

  • Inter-lab Comparison (Split Sample): If no formal EQAS exists for a specific parameter, send split sample to another NABL lab and compare results.
    LIS Security Audit: Who has access to edit reports?