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Unit 1 of 3 · B.Sc MLS Sem 4

Unit 1: Laboratory quality and organization

Clinical Biochemistry-1 notes · PTU syllabus (BMLS403-18)

3 min read3 topics9 exam questions
On this page
  1. Unit summary
  2. Hazards and safety measures
  3. Quality control and quality assurance
  4. Laboratory organisation, management and records
  5. Key terms
  6. Quick revision
  7. Important questions

Unit summary

A clinical biochemistry laboratory must be safe, organised and reliable. This unit covers hazards and safety measures, quality control and quality assurance, and laboratory organisation, management and record keeping.

After this unit you can

  • Identify hazards and apply safety measures
  • Distinguish quality control and quality assurance
  • Use Levey–Jennings charts and Westgard rules
  • Organise a laboratory and maintain records

PTU syllabus topics

  • Hazards and safety measures in the clinical biochemistry laboratory
  • quality control and quality assurance
  • laboratory organization
  • management and record maintenance
ClassificationQuality in the clinical lab
Quality assurance

  • Pre-analytical

    Right patient, sample, tube, transport

  • Analytical

    Internal QC with controls, calibration

  • Post-analytical

    Correct reporting and turnaround

  • External QC

    Proficiency testing against other labs

1

Topic 1

Hazards and safety measures

ComparisonHazards in clinical biochemistry
Examples
Safety measures

Biological

Serum, plasma, urine

Universal precautions, PPE, hepatitis B vaccination

Chemical

Acids, sodium azide, cyanide (Drabkin's), mercury, solvents

Fume hood, labelled containers, MSDS, spill kits

Electrical and mechanical

Analysers, centrifuges

Earthing, lids closed, balanced loads

Fire

Flammable solvents, gas

Extinguishers, storage cabinets

Ergonomic

Repetitive pipetting

Automated pipettes, breaks

2

Topic 2

Quality control and quality assurance

ComparisonQA and QC
Quality assurance
Quality control

Scope

Whole process — pre-analytical, analytical, post-analytical

Analytical phase

Aim

Reliable results and service

Detect analytical errors before reporting

Tools

SOPs, training, audits, accreditation (NABL, ISO 15189)

Control materials, QC charts, Westgard rules

Key termsTypes of QC
Internal QC
Control sera of known values run with every batch
External quality assessment (EQAS)
Unknown samples from an external provider (e.g., CMC Vellore, AIIMS) compared with peers
Precision
Closeness of repeated results (SD, CV)
Accuracy
Closeness to the true value
Key formulasQC statistics

  • Mean

    Sum of values ÷ number

  • Standard deviation

    Spread of values around the mean

  • Coefficient of variation

    CV% = SD ÷ mean × 100

  • Levey–Jennings chart: control values plotted daily against lines for mean ± 1, 2 and 3 SD.
Key termsWestgard rules
1₂s
One value beyond 2 SD — warning
1₃s
One value beyond 3 SD — reject (random error)
2₂s
Two consecutive values beyond 2 SD on the same side — reject (systematic error)
R₄s
Range between two controls exceeds 4 SD — reject (random error)
4₁s
Four consecutive beyond 1 SD on one side — reject
10x
Ten consecutive on one side of the mean — reject (shift)

Example

Glucose control mean 100 mg/dL, SD 2. Today's value 107 exceeds 100 + 3 × 2 = 106 → 1₃s violation; stop reporting, find and fix the error, rerun.

3

Topic 3

Laboratory organisation, management and records

ProcessLaboratory workflow
  1. 1

    Test request

  2. 2

    Patient preparation and sample collection

  3. 3

    Sample reception, labelling, barcoding

  4. 4

    Processing (centrifugation, aliquoting)

  5. 5

    Analysis with QC

  6. 6

    Technical and clinical verification

  7. 7

    Reporting and critical-value calling

  8. 8

    Sample storage and disposal

Key termsRecords to maintain
Sample and test registers
Or laboratory information system (LIS)
QC records
Charts and corrective actions
Equipment logs
Calibration, maintenance, breakdowns
Reagent records
Lot numbers, expiry, opening dates
Staff records
Training and competency
Reports
Retained per policy
  • Management: staffing, workload, inventory, turnaround time monitoring, cost control and continuous improvement.

Key terms

Quality assurance
Overall system ensuring reliable laboratory results
Internal quality control
Running known controls with patient samples
Levey–Jennings chart
Plot of control results against SD limits
Westgard rules
Rules for accepting or rejecting QC runs
Coefficient of variation
SD expressed as a percentage of the mean

Quick revision

  • Biological, chemical, electrical, fire, ergonomic hazards.
  • QA vs QC; internal QC and EQAS; precision and accuracy.
  • Mean, SD, CV; Levey–Jennings; Westgard rules.
  • Workflow; records; management tasks; NABL and ISO 15189.

Important exam questions

Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).

Short-answer questions

  1. Q1.Distinguish QA and QC.
  2. Q2.What is EQAS?
  3. Q3.Define coefficient of variation.
  4. Q4.What does the 1₃s rule indicate?
  5. Q5.Name three records kept in a laboratory.
  6. Q6.What is turnaround time?

Long-answer questions

  1. Q1.Describe hazards and safety measures in a clinical biochemistry laboratory.
  2. Q2.Explain quality control with Levey–Jennings charts and Westgard rules.
  3. Q3.Describe the organisation and record keeping of a laboratory.

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