NABL Issues Guidance Document for Medical Laboratories

The National Accreditation Board for Testing and Calibration Laboratories (NABL) has released an updated guidance document—NABL 112B (Issue 01, Amendment 01)—providing detailed operational requirements for medical laboratories and their sample collection facilities. The document outlines mandatory practices for maintaining sample integrity, preparing accreditation scopes, performing lot verification, and implementing algorithms for automated result reporting.

The guidance applies to all NABL-accredited and applicant medical laboratories and is designed to strengthen reliability, traceability, and uniform quality across the diagnostic testing ecosystem.

1. Strengthened Standards for Sample Collection Centres (SCFs)

The document emphasizes that sample integrity must be protected throughout collection, handling, transportation, and processing, as these directly influence test accuracy.

Types of Sample Collection Centres Recognized

NABL categorizes SCFs into:

1. Owned centres: directly operated by the laboratory or parent company.
2. Managed centres: not owned by the laboratory but operated fully under its control.
3. Franchisee centres: affiliated through agreements with hospitals or nursing homes.

Any additional sources of samples must be declared, though such sources cannot claim SCF recognition.

Mandatory Quality Requirements for SCFs

Laboratories must:

1. Incorporate SCF operations into their documented quality management system.
2. Maintain a Primary Sample Collection Manual covering collection, handling, transport, and safety procedures.
3. Ensure appropriate hygiene, environmental conditions, privacy, and adequate collection space.
4. Use suitable packaging, insulated containers, ice packs, or dry ice to maintain recommended sample temperatures.

Temperature Control Expectations

NABL recommends:

• Conducting pilot studies to determine transit time and temperature needs.
• Using data loggers inside sample packaging to continuously record transport temperatures.
• Rejecting samples that deviate from required temperature conditions.
• Immediately storing received samples at appropriate temperatures when not processed immediately.

SCFs must also follow Biomedical Waste Management rules, ensure safe transport of microbiology specimens, and maintain compliance with the latest Manual of Clinical Microbiology guidelines.

Training and Safety Requirements

SCF staff must receive documented training on:

• Sample collection, processing, packaging, transportation
• Biosafety, waste disposal, first aid
• Environmental maintenance and hygiene
• Spill management and needle-stick injury procedures

All training must be evaluated and records maintained.

Internal Audits and Assessment by NABL

• Laboratories must audit each SCF at least once a year.
• NABL may assess SCFs separately from the main laboratory.
• Major non-conformities may result in denial or withdrawal of SCF recognition.

Only SCFs declared to NABL may be listed on test reports or claimed as recognized facilities.

2. Guidance for Preparing Scope of Accreditation

To standardize scope submissions:

1. Laboratories must use model scope formats provided in NABL 112B.
2. %CV and Measurement Uncertainty must be calculated from IQC data, ideally near clinical decision levels.
3. Profile tests (e.g., LFT, lipid profile) must list each component parameter individually.
4. Enzymatic methodologies must specify the enzyme used.

Calculated Parameters

NABL requires:

• Inclusion of primary parameters in the scope if calculated parameters are offered.
• Use of scientifically justified, reference-backed formulas.
• QC evaluation (mean, SD, %CV) of calculated parameters similar to direct analytes.

3. Detailed Procedures for Lot Verification

The guidance prescribes verification steps for quality control materials, reagents, coagulation assays, and semi-quantitative urine strips.

Key Requirements

1. Run new and old QC lots in parallel and compare trends.
2. For chemistry reagents: test at least two patient samples or QC samples; results must fall within the analyte’s measurement uncertainty.
3. For CBC reagents: perform background checks and test with at least two patient samples.
4. For coagulation tests:
   • Verify PT reagent lot with 20 normal specimens (90% must fall within existing range).
   • Conduct correlation studies (R ≥ 0.97).
   • Validate INR and verify reference ranges.
   • For APTT reagents: correlation studies and potential heparin curve recalibration.

Urine Strip Lot Verification

1. Minimum two patient samples across different analyte levels must be compared for old vs new lots.
2. Automated urine analyzer strips must also undergo parallel testing.

4. Algorithm for Automated Selection and Reporting of Results

The guidance includes a visual workflow describing when results may be auto-released. Key checkpoints include:

1. Control values must be in range.
2. Results must fall within the instrument’s dynamic range.
3. Any issues (air bubbles, sample integrity, instrument errors) must be corrected before release.
4. Critical results must not be auto-released and require authorization.
5. Delta checks must fall within expected limits.
6. Only stable, validated results may be sent for automated reporting.