LAB-QM-ANA-001 — Quality Control Policy

1.0 Purpose

The purpose of this policy is to establish an effective internal quality control (IQC) system to continuously monitor the analytical performance, precision, and accuracy of examination procedures at Tarangnan Community Hospital Clinical Laboratory. This ensures test reliability and prevents the release of clinically compromised results.

2.0 Scope

This policy applies to all examination procedures performed within the Clinical Laboratory, including automated hematology, clinical chemistry, microscopy, and serology, and governs all Medical Technologists and Laboratory Aides handling analytical operations.

3.0 Definitions

• Accuracy — the closeness of agreement between an individual test result and the accepted true reference value.
• Precision — the closeness of agreement between independent test results obtained under stipulated conditions (reproducibility).
• Trend — a gradual, continuous shift of quality control observations away from the established mean in one direction over time.
• Shift — an abrupt, persistent change of quality control observations falling consistently on one side of the mean.
• Levey-Jennings Chart — a graphical run chart displaying quality control values over time with mean and standard deviation control limits.

4.0 Responsibility

4.1 Hospital Director

• Provides administrative resources, equipment maintenance contracts, and approved budgets for commercial quality control materials.
• Exercises executive oversight and approves policy revisions per Organization and Governance.

4.2 Pathologist

• Conducts clinical oversight and periodic review of quality control performance, monthly imprecision trends, and multi-rule selection.
• Reviews and authorizes root-cause investigations and corrective actions for significant analytical failures per Organization and Governance.

4.3 Chief Medical Technologist / Laboratory Quality Manager

• Formulates, verifies, and supervises the laboratory-wide internal quality control program in accordance with DOH and ISO 15189:2022 standards.
• Reviews and signs routine QC records weekly and conducts monthly statistical performance evaluations (CV% and SD).
• Halts examination testing and directs corrective actions when unresolvable out-of-control conditions occur.

4.4 Medical Technologists

• Analyze commercial control materials at required daily frequencies prior to processing patient specimens.
• Review and evaluate daily QC runs against established control limits and Westgard multi-rules before releasing examination results.
• Document troubleshooting steps, withhold patient results during control failure, and inform the Chief Medical Technologist.

4.5 Laboratory Aides

• Assist in logging room temperature and receiving unopened control shipments under Medical Technologist direction.
• Shall never perform, calibrate, calculate, interpret, or authorize quality control or patient diagnostic results.

5.0 Policy / Procedure

5.1 Policy Statement

The laboratory shall maintain an internal quality control program meeting DOH licensing standards and ISO 15189:2022 principles. All examination methods shall be verified using statistical quality control materials prior to releasing patient results. Out-of-control analytical runs shall result in immediate testing cessation, root-cause investigation, and documented corrective action before resumption of testing.

5.2 General Guidelines (Waived and Non-Waived Tests)

• Commercial controls and calibrators of human origin shall be handled with universal biohazard precautions.
• Control materials shall be reconstituted, handled, and stored strictly in accordance with manufacturer instructions.
• Expired or improperly stored quality control materials shall never be used for analytical validation.
• Calibrated automatic pipettes or Class A glassware shall be used for reconstituting lyophilized controls.
• At least two levels of control materials shall be analyzed daily for each quantitative analyte prior to patient specimen testing. For qualitative tests, positive (or reactive) and negative (or non-reactive) controls shall be analyzed with each testing run.
• Control samples shall be processed, handled, and tested in the exact same manner as patient specimens by testing Medical Technologists.
• Patient results shall not be authorized or released until quality control results are verified to be within established acceptable limits.
• Any analytical run violating active rejection rules requires immediate quarantine of results and documented corrective action.

5.3 New Control Lot Verification

• Manufacturer package insert values and ranges shall serve only as preliminary guides during initial verification.
• A new quality control lot shall be analyzed in parallel with the current in-use lot for at least 5 days in duplicate to verify that observed means fall within acceptable manufacturer tolerances before placing the lot into routine service.

5.4 Establishment of In-House Mean and Control Limits

• In-house mean, standard deviation (SD), and coefficient of variation (CV%) shall be determined after collecting a minimum of 20 measurements across at least 10 testing days.
• The calculated in-house control limits (±1SD, ±2SD, ±3SD) shall be plotted on Levey-Jennings charts or configured in analyzer software and the non-interfaced TCH LIS.

5.5 Routine QC Operation

• Testing Medical Technologists shall run quality control materials at the beginning of each testing shift and after any major instrument maintenance or reagent lot change.
• Results shall be recorded immediately and verified against active multi-rules before testing patient samples.
• The Chief Medical Technologist / Laboratory Quality Manager shall conduct periodic weekly reviews and sign control records.

5.6 Monthly Monitoring of QC Data

• Monthly cumulative means, standard deviations, and CV% values shall be calculated and tabulated for all quantitative examination procedures.
• Imprecision trends and cumulative Total Allowable Error (TAE) shall be evaluated against established analytical goals derived from authoritative literature (e.g., CLIA criteria).
• Any significant drift, shift, or unacceptable precision degradation shall trigger a formal investigation and preventive action.

5.7 Quality Control Charting

• Control results shall be charted on Levey-Jennings graphs manually or via onboard analyzer software.
• Control charts shall clearly indicate the analyte, instrument identity, control lot number, expiration date, mean, and standard deviation limits.

5.8 Interpretation of QC Results — Westgard Multi-Rules

The laboratory employs Westgard multi-rules to distinguish random error from systematic error (see Figure 1):

Figure 1 — Daily internal quality control and Westgard rule troubleshooting flow

• 1-2S (Warning): One control value exceeds the mean ±2SD. Triggers inspection of the analytical run, but patient results may be released if no other rule is violated.
• 1-3S (Rejection — Random Error): One control value exceeds the mean ±3SD. Run is rejected.
• 2-2S (Rejection — Systematic Error): Two consecutive control values exceed the same mean +2SD or −2SD limit. Run is rejected.
• R-4S (Rejection — Random Error): One control value exceeds the mean +2SD and another exceeds the mean −2SD in the same run. Run is rejected.
• 4-1S (Rejection — Systematic Error): Four consecutive control values exceed the same mean +1SD or −1SD limit. Run is rejected.
• 10x (Rejection — Systematic Error): Ten consecutive control values fall on one side of the mean. Run is rejected.

5.9 Corrective Actions for Controls Out of Limits

• Testing of patient specimens shall cease immediately upon violation of a rejection rule.
• The Medical Technologist shall inspect the error type (systematic versus random) and investigate probable root causes: - Reagent stability, deterioration, or expiration; - Control material degradation, improper reconstitution, or evaporation; - Instrument sampling, optical, temperature, or hydraulic malfunction; - Recent recalibration or lot transitions.
• Corrective measures shall be executed and fresh control aliquots analyzed. Patient testing shall resume only when control values return to in-control status.
• Patient specimens tested between the last acceptable control run and the failed run shall be evaluated, recalled, or retested if clinically indicated, logged in accordance with Occurrence Management Policy.
• All troubleshooting actions and findings shall be documented on the control troubleshooting log.

5.10 Documentation and Record Retention

• Daily quality control printouts, Levey-Jennings charts, and calibration logs shall be filed in the respective section dossiers.
• All quality control records, monthly performance summaries, and corrective action reports shall be retained in accordance with Laboratory Retention Schedule Policy.

6.0 Records

The following controlled records are maintained under this policy:

These records are maintained electronically in analyzer memory, the LIS, and dedicated electronic workbooks registered under F-QM-002-B-V0 (Decision D5); no separate paper form is maintained for them.

7.0 References

• DOH QMS Tool, Section 4 (Monitoring Performance — Internal Quality Control)
• DOH Administrative Order No. 2021-0037, Annex B1 (Technical Standards for Clinical Laboratories)
• ISO 15189:2022, Clause 7.3.7.2 (Internal quality control)
• WHO LQMS Handbook, Chapter 6 (Process control — Introduction to quality control)
• CLSI C24-A3, Statistical Quality Control for Quantitative Measurement Procedures

Companion policies:

• Method Validation Policy — Method validation and analytical performance verification
• Occurrence Management Policy — Incident reporting and management of nonconforming testing events
• Laboratory Retention Schedule Policy — Retention schedules for internal quality control records and charts

Controlled visual annex:

• IG-16 — IQC Westgard Troubleshooting — one-page visual annex to this policy, controlled under Document Control Policy Section 5.2.6 and registered in F-QM-002-B-V0. Master files: infographics/IG-16-IQC-Westgard-Troubleshooting-LAB-QM-ANA-001.png (PNG, print PDF, and editable HTML).