Quality assurance in
Public health
Microbiology
Quality Assurance Definition.
• All planned and systematic actions necessary to
provides adequate confidence that goods or services
will satisfy the customer's needs. (OR )
• The right result at the right time on the right
specimens; from the right patient with result
interpretation based on correct reference data and at
the right prices.
 It consists of,
• Quality control.
• Quality assessment .
• Quality improvement.
• Laboratory Testing Impacts Nearly Everyone
• Accurate, reliable lab testing is essential to all aspects
of health care including public health microbiology.
• How do we achieve QUALITY? excellent performance
in public health microbiology laboratory?
• Quality is achieved by:
• Determining the customer precise requirements
• Ensuring that all resources, facilities and skills
required to meet the customer requirements are
available from the public health microbiology
points.
• Planning, documenting and implementing
management procedures to ensure that the
customer’s requirements are met constantly.
Ensuring that staff are trained and provided the
resources to do the job right the first time.
• Undertaking regular reviews and audits of all process
• Total organized commitment from management.
Quality Management Systems Comprises:
• Training and ongoing support of all staffs
• Providing quality services to the users of public health
microbiology laboratory
• Management of equipments and supplies
• Management of finance and budgets
• Quality assurance, QC, External quality assessment
(EQA), Accreditation, SOPs and Good Communication
•
• Quality issues concerning public health
microbiology could be unique in :• It focuses more on environmental samples
• It should also assess the ability of the laboratory
to detect agents of disease during emergency.
• Sampling issues is also critical, say during water
sampling, air sampling, soil sampling.
• Quality assurance pertaining public health
microbiology includes:
• Preanalytical components
• Analytical components
• Post analytical components
Preanalytical issues of public health microbiology lab :
It includes the following points but not only limited to:
• Proper laboratory setup (organization)
• Adequate trained personnel
• An up to date equipments
• Proper specimen management
1.Laboratory Organization (set up).
• As clinical microbiology laboratory, the organization of public
health microbiology lab. may be demanding
• There must be adequate space / rooms for each sections:
o Specimen receipt, Specimen analysis
o Section for bacteriology, Mycobacteriology, Virology, toxins
detection (serology). Media and reagent preparation
(sterilization room)
o Adequate and appropriate stores for reagents, control
materials
• Laboratory benches should be suitable for the intended
purpose
• Properly designed
• Easily cleaned
• Resist chemicals : acids, bases, and other chemicals
• Have good electrical system that can fit with the various
instruments
• Could have compartments for inoculation, gram staining
(sinks), microscopic examination, etc.
2.Adequate trained personnel :-
• Public health microbiology
• Virology
• Mycology/ toxins
• Laboratory quality officers / managers
• Data managers etc
3. Adequate equipments and consumables:• Incubators, Autoclaves, Centrifuges, Homogenizers, Mixers,
Shakers, Safety cabinet, Weighing balances.
o Distillers for distilled water preparation
o Deionizers : ion free water
o Specimen containers different types-- Test tubes,Flasks, Bottles, etc.,
various glass wares: Test tubes, Measuring cylinder, Flasks etc.,
• Consumables
 Media of different types
– Solid: blood agar, TCBS agar, chromagar
– Semisolid: SS,: Liquid :TCBS, Alkaline peptone water etc.
 Antimicrobial discs for AST
 Calipers for measurements
 Membrane filters
 MacFarand standards
 Antiseptics and disinfectants
• 75 % alcohol, Phenol, Bleach solution, Savlon
– Buffer solutions of different types
• Tris buffer. Phosphate buffered saline solutions ( PBS)
4. Specimen management issues
– Environmental samples such as food, water, milk and beverages are
more common.
– SOPs is the key for quality
– Specimen receipt guidelines should be available
– All specimens must be adequate in volume
– Proper labeling is critical
– There must be specimen transportation protocol
• Analytical aspects of public health microbiology
o Once the sample is properly collected it has to be analyzed according to the
required quality
o It includes the following issues :• Calibration of equipments like pipettes, dispensers,
• Running of quality control samples
• Negative and positive quality control samples are required for :• Staining solutions, Culture media , AST and
• Result interpretation and verification
• Calibration is indicated
• Whenever new equipment is installed
• During change in spare parts
• As it is required by the SOP for a particular tests
• This is true for pH meter for every pH measurement
• Quality control issues concerning culture media
• Any culture media should be prepared aseptically
• Sterility testing is an acceptable quality control measures for
culture media:• 5 % of new culture media should be incubated at 37 o C for
48 hrs.
• If there is contamination another 5% of the batch is
repeated. If there is no contamination that is ok
• If contamination persist, new batch of media will be
prepared.
• In addition measures has to be taken to avoid contamination
during :• Cleanliness of room
• Preparation of distilled and de-ionized water
• Limited access to microbiology laboratory
 Proper use of refrigerator, incubator, etc
• Store one item in one refrigerator/ different compartment
• Never store samples, culture media in the same refrigerator
• Volume of items stored/ kept must be proportional with the
intended purposes.
• Quality control measures related to staining solution
• Staining solution must be free from contaminants
• It has to be filtered
• Known gram negative and gram positive control slides/
materials must be run for new batch of stain and according to
SOP of each procedures.
• It should be with in the expiry date
• Quality control issues concerning AST
• Once microbes are isolated from samples drug resistance
pattern can be done
• Pure culture must be prepared
• The AST methods must be standardized (WHO
recommendation)
• McFarland standard solution is very useful to prepare
standard inoculum / suspensions.
• Standard organisms with known sensitivity pattern must
be used :
• ATCC ( American Type Culture Collection system)
• A new reference culture should be purchased annually.
• Working culture can be maintained at 4°C for four weeks.
• Recommended antimicrobial discs must be used.
• Antimicrobial discs should be stored at
refrigerator temperature(2-8°C)
• It has to be used with in the expiration date.
• Caliper for measurements for zone of inhibition is
vital.
• Result interpretation and verification
• Result must be interpreted according to SOP
• Any result that is sent to requester must be
verified by the laboratory manager / head
responsible for that unit.
• Screening tests should be confirmed
External quality assessment (EQA) issues
• This is a system that allow participation of particular
laboratory to compare it’s performance with others.
• It should be given by an external laboratories (national
and international)
• It can be achieved by :
• Onsite supervision
• Proficiency testing
• Blind rechecking of the laboratory results
• Onsite supervision of public health laboratory
• It gives chance to observe all laboratory stet up and
activities
• It is best but expensive.
• Required by accreditation bodies
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 Proficiency testing
Unknown water / milk sample could be sent to laboratories
The laboratory can analyze for the requested tests
The performance is compared with PT providers
o It does not assess the over all performance of the lab
o Give chances for improvement
o It should be continuous
Blind rechecking
• Samples analyzed for microbiological purpose will be
repeated by the external bodies.
• Results will be communicated.
• Remedial actions will be taken by the participant labs.
• It is demanding
• Limited EQA systems are available for public health
microbiology labs.
Post-analytical issues in public health microbiology
– It includes matters such as:
• Recording
• Documentation
• communication
• sample retention issues.
Safety in public health microbiology laboratory
• All necessary safety measures should be taken
• Safety measures must be available related to infectious and
non infectious substances
• Waste management issues.
• Hazard related to sample processing and sample
transportation must be assessed.
• Safety and personal protective equipment
must be available
• Gloves, gowns , biohazard bags
• Goggles, Masks in case of epidemics and
routine activities
• Shower must be there
• First aid measures should be available
• Good attitudes towards hand hygiene practice
is essential