This document discusses quality assurance and quality control procedures for microlaboratories. It defines quality and quality management, and explains how quality is ensured in laboratories through controlling all factors that influence reliable test results. Quality assurance aims to ensure accurate and reliable data generation and use. Key quality control procedures discussed include regular equipment maintenance and calibration, sterilization validation methods, reagent and media quality control, and environmental monitoring. Adhering to these standardized quality control protocols is important for generating credible results and safeguarding patient health.

1. Quality Assurance & Quality
Control in Microlabs
Dr Mostafa Mahmoud Ahmed, Ph D
Consultant Microbiologist, GDHA, Riyadh, KSA.
Associate Prof. of Microbiology & Immunology.
Faculty of Medicine – Ain Shams University

2. The standardized definition of quality refers to
all those features of a product (or service) which
are required by the customer.
“Quality management“ means what the
organization does to ensure that its products or
services satisfy the customer's quality
requirements and comply with any regulations
applicable to those products or services.
Definition of Quality & Quality Management

3. How do you ensure quality in
laboratory?
•By controlling all the factors that
influence generation of reliable results

4. Quality Assurance (QA)
The sum total of all activities that
are performed to ensure quality of
the product
Regarding the clinical lab:
• QA is the sum total of all activities that are
undertaken to ensure generation, and utilization, of
reliable and accurate results/data

5. Objectives of quality in lab
Support provision of high quality health-care
–Reduce morbidity
–Reduce mortality
–Reduce economic loss
• Ensure credibility of lab
• Generate confidence in lab results

6. Consequences of poor quality
• Inappropriate action
– Over-investigation
– Over-treatment
– Mistreatment
• Inappropriate inaction
– Lack of investigation
– No treatment
• Delayed action
• Loss of credibility of laboratory
• Legal actions.

7. Factors influencing quality
Sample
Receiving
Analysis
Reports
Doctor
Patient
Requisition
Patient
Preparation
Sample
Collection
Sample
Handling
Sample
transport

8. Factors affecting quality (Analytical)
• Proficiency of personnel
• Reagents stability, integrity and efficiency
• Equipment reliability
• Specificity & sensitivity of selected test
• Procedural reliability using standard operating
procedures
• Use of appropriate controls
• Documentation
• Assessment

9. Maintenance and Quality Control of
Laboratory Equipment

10. Factors affecting the optimal utilization/
performance of equipment:
• Proper installation
• Calibration
• Validation
• Regular maintenance (including the
preventive ones)
• Training of operators

11. Pre-purchase QC considerations for
instruments/equipment
• Purchase instruments/equipment from reputed manufacturers,
with long standing, and who in turn practice Quality Standards
and GMP.
• Specifications should fit the intended purpose, with comparative
cost-effectiveness-compatible with availability of reagents on
long term basis.
• Specifications should conform to local conditions (power supply,
humidity and other climatic factors).
• Maintenance service (through AMC or other channels) should be
preferably local, prompt, and cost-effective
• Should not be a very complex instrument -technical safety and
moderate running cost.
• Operating Manual -containing also the instructions for
maintenance and “trouble shooting” list-should be provided.

12. The Equipment File Form
1. Unit identification:
• Name of the Unit ___________________________________
• Manufacturer ____________________________________
• Serial No.____________________________________
• Model No.____________________________________
• Hosp./Lab No.____________________________________
• Location____________________________________
2. Warranty information:
• Date of Purchase____________________________________
• Date Received____________________________________
• Manufacturer’s Warranty #
• Covers a) ______________ From _______ To ________
b) _________________ From _______ To________
c) _________________ From _______ To ________
• For Service, call _____________________________________
• Address_____________________________________
• Telephone #_____________________________________
• Other Warranties
• Name _____________________________________
• Address_____________________________________
• Telephone #_____________________________________
• Covers a) ________________ From ________ To ________
b) ________________ From ________ To ________

13. The Equipment File Form (Contd.)
3. Service Contracts:
Name --------------------------------------------------------------------------
Address_____________________________________
Telephone #__________________________________
Covers a) ________________ From ________ To ________
b) ________________ From ________ To ________
c) ________________ From ________ To ________
4. Performance Monitoring:
Frequency Nature of Maintenance
_____________ ___________________________________
----------------------- -----------------------------------------------------------
----------------------- -----------------------------------------------------------
5- other files to be included:
• User’s manual
• Incident reports
• Training and privileged persons for this equipment

14. Microscopes (bright field)
Action required After use Daily Weekly Annually
Clean oil immersion & objective
lens paper
*
Remove slides *
Cover microscope with dust cover *
Adjust optic system *
Clean optic system & microscope *-
Overhaul microscope *

15. Centrifuges
• Before using, ensure that -the heads are
symmetrically loaded ; the tube caps are sealed
tubes are in safety centrifuge cups ; swinging
buckets are symmetrically arranged.
• Check the centrifuge, after each run, for
cleanliness and accidents.
• Centrifuge is calibrated with a tachometer or
strobe light annually/ semiannually, depending
upon frequency of its usage.

16. Centrifuges checklist
Action required Quarterly Semiannually Annually
Check with
tachometer/strobe
* Or *
Check timer *
Check brushes & internal
parts
*
Check balance of rotors &
trunnions
*
Recertify *

17. Freezers, Incubators & Refrigerators
• A Temperature log sheet should be placed on
each piece of equipment, and the temp. be
recorded first thing in the morning.
• A temperature variation of ± 1 0C is acceptable
for most pieces of equipment
• If 37 0C is desired, then set the instrument at 36
0C.

18. Freezers, Incubators & Refrigerators
checklist
Function Daily Monthly Quarterly Semi-
annually
Check temperature *
Check pilot lights *
Check doo-seal *
Defrost, clean or
both
*
Recalibrate
thermometer
*
Check level *

19. Incubators
Calibration-corrected temperature recorded
twice daily for days in use, readings separated by
at least 4 hours.
Refrigerator
Temperature recorded for days in use, at
least once per day.

20. Water Baths
- Should be filled with only distilled water (to
prevent accumulation of salts on the walls)
- Temperature variation of ±1 0C is acceptable
Function Daily Monthly Semi-annually
Record
temperature
*
Check water
level
*
Replace water *
Clean bath *
Recalibrate
thermometer
*

21. Autoclaves
• Should be checked each Friday with
commercially available spore strips. This will
enable incubation of the strips over the week
end, with final report by Monday.
• Whenever materials are being autoclaved in
autoclave bags, do not tie the bags tightly, to
permit the steam to permeate into all parts
within the bag.

22. Autoclave
Function Each
load
Weekly Monthly Semi-
annually
Record temperature &
pressure
*
Sensitive indicator tape *
Spore strip *
Clean autoclave *
Check doo gasket *
Recalibrate and check temp
and pressure & timer
*

23. ELISA READER
• Special precaution:
• Keep the top of the Reader clear; to avoid over
heating, the cooling fan inlet must not be blocked
or covered
• Place the Reader on a flat surface, free of dust,
solvents, acidic vapours, vibration and direct
sunlight
• Reader should be away from freezers, so that cold
wet objects will not be placed on it inadvertently

24. QC procedure and routine maintenance
Frequency Activity
Daily Clean plate carrier, top of instrument and display
window
Every 3
months
Clean air filters (if applicable) Clean and lubricate plate
support guide bar
Every 6
months
Check-Linearity; Repeatability; Diode; Accuracy; and
Mechanical alignment

25. Hot Air Oven
• Used for drying glass ware
• To sterilize metal and some high temperature-stable glass objects
• General precautions:
– Place on a level bench top
– Not near autoclaves, direct sun light or areas exposed to heat
– At least 5 cm (2”) space all-round the oven, to facilitate air-circulation.
– No explosives, combustibles or flammables in oven
– Do not heat food, oily reagents in oven
– Do not sterilize liquids in hot-air-oven
– Do not stack glass ware; may lead to breakage
– Do not sterilize powders, oily substances and standard glass ware by dry
heat
• Routine QC:
• 1. Record oven temperature each time it is used
• 2. Semi-annually, clean up the interior parts
• 3. Calibrate the gauge or Hg-bulb thermometer once every 6 months, using
a standard thermometer.

26. Biological Safety Cabinets
• Whenever the cabinet is in use, nothing should be
placed on the grid panels, as this could disrupt the
air-flow pattern
• Air velocity across the opening of the cabinet
should be at least 75 linear ft./min. (The National
Sanitation Foundation (NSF) Standards. For Class-II,
cabinets) ; cabinet should be set at 90 –100
lft./min., across the opening of the cabinet
• UV lamp to be replaced when the output is 70% or
less of its initial rated output (= 253.7 nm)

27. Biological Safety Cabinets checks
Action Required Daily Bi-
monthly
Monthly Semi-
annually
Check air pressure gauge *
Check air-flow pattern
(with a smoke stick)
*
Disinfect the cabinet *
Check air velocity (across
front)
*
Clean UV Lamp (with
alcohol gauze)
*
Check UV lamp output *
Recertify cabinet *

28. pH Meter
Action Required Each use Daily
Set temperature compensation (if not
automatic)
*
Standardize against certified buffer *
Check electrode *
Ensure that electrode is immersed in neutral
buffer
*
• Meter standardized each use period with pH 7.0
and either 4.0 or 10.0 buffers, with date and
buffers recorded in log book.
• Commercial buffer solutions dated when
received and opened and discarded by
expiration date.

29. Pipettes
• Of various kind –to deliver milliliter to micro liter volumes,
manual or automated, repeater, adjustable volume, single or
multichannel models.
• Basically, it is either air-displacement mechanism or those
which use a plunger mechanism; in general, the positive
displacement pipettes (plunger type) are considered more
accurate for small volumes.
• Volumetric measurement using pipettes is potential source of
error in a microbiology laboratory.
• A small error in pipetting can cause a large error in the final
result. Pipettes are used for a number of important purposes –
to dilute sera, set up quantitative cultures, to prepare inocula
for antimicrobial susceptibility tests, to add ingredients to
media/reagents or specimen during test procedures etc.
• It is therefore very important that the accuracy and precision of
the pipettes is maintained at all times.

30. Pipettes maintenance
Calibration methods for pipettes: Gravimetric,
spectrophotometric , and colorimetric methods are the
most convenient and commonly used.
Method Basis Limitation
Gravimetric 1 ml of water = 1 g
Volume. Dispensed must
(adjusted for
temperature & pressure)
Volume dispensed
must be > 0.002 ml
Spectrophotometric Absorbance of K2Cr2O7
used to create calibration
curve
Volume dispensed
must be > 0.01 ml
Colorimetric (for
quantitative loops)
Absorbance of Evans blue
dye used to create
calibration curve
Loop volume between
0.01-0.001 ml

31. Calibration of pipettes: special precautions
• Use the same tip for all deliveries during the calibration
procedure, whether the pipette is used for repetitive
dispensing of several aliquots of same liquid OR for
transferring single aliquots of different liquids.
• ‘Prerinsing’ is precoating of the inside of the tip with the liquid
being dispensed. Aspirate an aliquot of the liquid into the tip,
and then dispense it back into the original container or discard
it. Prerinsing improves the uniformity and precision by
providing identical contact surface for all aliquots.
• Temp. of pipettes to be calibrated, room air, test liquid (water)
and other equipment should be identical (±0.5 0C)
• Use water with no visible air bubbles; air bubbles alter
measured volumes.
• Complete weighing step quickly. Use a lid on the weighing
vessel to decrease evaporation. This will obviate the need for
an evaporation factor in the calculations.

32. Analytical Balances
Action needed Each
use
Daily Quarterly Annually
Use weighing papers/boats *
Clean pan & base of balance * *
Ensure balance level *
Adjust zero point *
Lubricate when necessary *
Calibrate with standard
weights
*
Recertify balance *

33. Balance
• Calibrated monthly using American Society for
Testing and Materials (ASTM) type 1,2 or 3
weights (minimum of 3 traceable weights which
bracket laboratory weighing needs.)
• Non-reference weights calibrated every six
months with reference weights.
• Annual service contract established, records
available of most recent calibration and
correction values on file and used.
• Reference weights recertified if damaged or
corroded.

34. Methods of Validating Sterilization
ProcessesProcess Physical Methods Chemical
Methods
Biological Methods
Dry Heat Temperature
Recording Charts
Colour Change
Indicators*
Bacillus subtilis **
(ATCC # 9372)
Moist
Heat
Temperature
Recording Charts
Colour Change
Indicators*
Bacillus
stearothermophilus**
(ATCC #7953)
* “OK Indicator Strips” = what is the manufacturer?
“Self Adhesive Autoclave Tape” = Manufacturer ??
“Self Adhesive Dry heat Label” = manufacturer ??
“Temperature” Indicators- for steam and dry sterilization
**As spore strips and Prospore ampoules (105-106 spores
/strip or ampoule)

35. Biological Sterilization Indicators
Sterilization Method Biological Indicator
Steam Bacillus stearothermophilus
Dry Heat Bacillus subtilis var. niger
Ethylene Oxide Bacillus subtilis var. globigii
Ionizing Radiation Bacillus pumilus
Filtration Pseudomonas diminuta
Heat resistant spores of B. stearothermophilus are dried on paper
treated with nutrient medium and chemicals.
After sterilization, the strips are incubated for germination and
growth.
A colour change indicates whether they have or have not been
activated.

36. Quality Control of glassware
• All chipped, damaged or etched glassware
should be discarded to prevent accidents.
• Sterilized glassware must be checked for sterility
on a regular basis, and then stored for not >3
weeks prior to use.
• Sterilized glassware as well as clean glassware
should be covered with aluminum foil.
• All glassware should be free of detergent.

37. Glassware/ Plasticware
• Graduated cylinders and precalibrated containers
used to measure sample volumes accurate with a
tolerance of 2.5% or less.
• Glassware inhibitory residue test performed on
initial use of washing compound and whenever
different detergent used.
• Batches of dry glassware spot-checked for pH
reaction.
• Sterility of each lot of sample containers confirmed
by adding sterile non-selective broth to at least
one container, incubating at 35 oC for 24 hours and
checking for growth.
• Sample bottles hold at least 120 ml and have
dechlorinating agent.

38. Thermometers
• Glass and electronic thermometers calibrated
annually, dial thermometers quarterly, at the
temperature used, against reference National
Institute of Standards and Technology (NIST)
thermometer.
• Calibration factor marked on thermometer and
calibration date and factor recorded.
• Thermometers discarded if off more than 1 oC from
reference thermometer.
• N.B. NIST stops supporting mercury thermometers
starting from 1-3-2011

39. UV Lamp
• If used to sanitize, tested quarterly with meter
or by agar spread plate method.
• •UV lamp for fluorogenicmethods should be 6
watt.

40. Reagent-Grade Water
• Quality of reagent water should be tested for:
• Conductivity
• Heavy metals
• Chlorine residual
• Heterotrophic plate count bacteria
• Bacteriological quality of reagent water

41. Dilution/ Rinse Water
• Each batch of dilution/rinse water checked for
sterility by adding 50ml of water to 50ml of
double-strength non-selective broth. Incubate
for 24 hours at 35oC and check for growth.

42. Laboratory Media Preparation
Records Should Include:
• Date of preparation
• Type of medium
• Lot number
• Sterilization time and temperature
• Final pH
• Technician’s initials
• Each new batch of laboratory prepared
medium checked before use with positive and
negative culture controls and results recorded.

43. Thank You