Unit 1: Role, ethics and laboratory basics
Basics of Biochemistry notes · PTU syllabus (BMLS103-18)
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Unit summary
Accurate results start with a safe, well-run laboratory. This unit covers the role of the medical laboratory technologist, ethics and responsibility, safety measures and first aid, cleaning and care of glassware and equipment — soda-lime and borosilicate glass — and preparing chromic acid cleaning solution.
After this unit you can
- Describe the role and ethics of a medical laboratory technologist
- Apply laboratory safety measures and first aid
- Clean and care for glassware and equipment
- Prepare chromic acid cleaning solution safely
PTU syllabus topics
- Role of the medical lab technologist
- ethics and responsibility
- safety measures and first aid
- cleaning and care of glassware and equipment (soda lime and borosil glass)
- preparation of chromic acid solution
Personal protection
Lab coat, gloves, goggles
Never pipette by mouth
Use pipette fillers
Chemical handling
Label and store correctly
First aid
Eye wash, spill kit
Waste disposal
Segregate by colour code
Topic 1
Role of the medical laboratory technologist
- Pre-analytical
- Patient identification, sample collection, labelling, transport and storage
- Analytical
- Performing tests accurately with quality control
- Post-analytical
- Recording, verifying and reporting results; critical values communicated promptly
- Equipment
- Calibration and maintenance
- Quality
- Internal QC, external quality assessment, NABL standards
- Safety
- Following biosafety and waste rules
Topic 2
Ethics and responsibility
- Confidentiality
- Patient results disclosed only to authorised people
- Accuracy and honesty
- Never alter or fabricate results
- Respect
- Treat every patient with dignity, without discrimination
- Informed consent
- Explain procedures; consent for tests such as HIV
- Competence
- Work within training; keep learning
- Accountability
- Report errors and correct them
Topic 3
Laboratory safety measures
Biological
Blood, body fluids, cultures
PPE, universal precautions, hepatitis B vaccination
Chemical
Acids, alkalis, toxic and flammable reagents
Fume hood, labels, MSDS, never add water to acid
Physical
Heat, glass cuts, electricity, centrifuges
Heat-proof gloves, balanced centrifuge, earthed equipment
Fire
Spirit, ether, gas burners
Extinguishers (CO₂ for electrical), fire exits, no open flames near solvents
Topic 4
First aid in the laboratory
Acid or alkali on skin
Wash with plenty of running water for 15 minutes
Remove contaminated clothing; seek medical help
Chemical in the eye
Rinse at the eyewash station for 15 minutes, eyelids open
Ophthalmologist
Cuts from glass
Remove glass, wash, apply pressure and antiseptic
Dressing; tetanus if needed
Needle-stick injury
Let it bleed, wash with soap and water; do not scrub
Report; post-exposure prophylaxis within 2 hours for HIV risk
Burns
Cool under running water for 20 minutes
Cover with sterile dressing
Swallowed chemical
Rinse mouth; do not induce vomiting
Emergency care
- Golden rule: always add acid to water, never water to acid.
Topic 5
Glassware: soda-lime and borosilicate
Composition
Silica, soda, lime
Silica with boron oxide
Heat resistance
Low; cracks on heating
High; low thermal expansion
Chemical resistance
Less; alkali leaches
High
Use
Disposable tubes, slides, bottles
Beakers, flasks, test tubes for heating
Topic 6
Cleaning and care of glassware and equipment
- 1
New glassware
Soak in 1% HCl overnight to remove free alkali, then wash
- 2
Used glassware
Decontaminate (autoclave or hypochlorite)
- 3
Wash with detergent and brushes
- 4
Rinse with tap water
- 5
Soak greasy glassware in chromic acid
- 6
Rinse thoroughly with distilled water
- 7
Dry in an oven (not volumetric glassware at high heat)
- Pipettes: soak in a pipette jar of disinfectant, then wash in a pipette washer. Equipment care: follow manufacturer schedules, keep log books, clean spills immediately, cover instruments when not in use.
Topic 7
Preparing chromic acid cleaning solution
- 1Dissolve about 100 g potassium dichromate in 100 mL water (warm to dissolve)
- 2Cool the solution
- 3Slowly add concentrated sulphuric acid to make 1 litre, stirring, in a glass vessel kept in cold water
- 4Store in a glass-stoppered bottle
- 5Discard when it turns green (reduced chromium)
- Caution: highly corrosive and toxic (chromium VI); wear gloves, goggles and apron; work in a fume hood. Many laboratories now use safer detergent cleaners.
Key terms
- Pre-analytical phase
- Steps before testing, such as sample collection
- Confidentiality
- Protecting patient information
- MSDS
- Material safety data sheet for a chemical
- Borosilicate glass
- Heat-resistant laboratory glass
- Chromic acid
- Strong oxidising cleaning solution
Quick revision
- MLT roles: pre-analytical, analytical, post-analytical.
- Ethics: confidentiality, accuracy, consent, accountability.
- Hazards and precautions; first aid for chemicals, cuts, needle-stick, burns.
- Soda-lime vs borosilicate.
- Glassware cleaning; chromic acid preparation and safety.
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
- Q1.State three duties of an MLT.
- Q2.Why is confidentiality important?
- Q3.What should be done after a needle-stick injury?
- Q4.Why add acid to water and not water to acid?
- Q5.Distinguish soda-lime and borosilicate glass.
- Q6.When should chromic acid be discarded?
Long-answer questions
- Q1.Describe the role and ethical responsibilities of a medical laboratory technologist.
- Q2.Describe laboratory safety measures and first aid.
- Q3.Describe cleaning of glassware and preparation of chromic acid.
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