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QUALITY MANAGEMENT IN MICROBIOLOGY LAB By-Dr. Prafulla Songara 3rd year P.G. Department of Microbiology LHMC


WHAT IS QUALITY Degree of congruence between expectation and realization WHO DEFINITION Quality means meeting the predetermined requirements of users for a particular substance or service


QUALITY CONTROL Control of errors in the performance of tests & verification of test results Must cover all aspects of every procedure within the department Must be practicable, achievable & affordable


QUALITY ASSURANCE(QA) Total process whereby the quality of laboratory reports can be guaranteed “the right result, at the right time, on the right specimen from the right patient, with the result interpretation based on correct reference data and at the right price” QA=IQC+EQA

INTERNAL QUALITY CONTROL(IQC) Set of procedures undertaken by the staff of a lab for continuously & concurrently assessing laboratory work & the emergent results EXTERNAL QUALITY ASSURANCE (EQA) System of objectively assessing the laboratory performance by an outside agency.


COMPONENTS OF A QA PROGRAMME Personnel with adequate training & experience Proper specimen collection Employment of techniques with precision & accuracy Proper performance of tests Efficient processing of results Reagents & equipments of good quality Methods of detecting errors Corrective steps when analyses go out of control Continuous training of staff Documentation Co-ordination Timely feedback


FACTORS INFLUENCING QUALITY Collection of specimen Patient preparation Handling Requisition Transportation Patient Specimen Receipt Physician PRE-ANALYTICAL FACTORS ANALYTICAL FACTORS Performance of test in laboratory POST-ANALYTICAL FACTORS Interpretation Results Reports


PRE-ANALYTICAL FACTORS Right investigations Right Sample Right Technique Right Laboratory Right Transportation Right Quantity Right labeling


ANALYTICAL FACTORS Equipment reliability Reagent stability, integrity & efficiency Adequate calibration Correct interpretation Procedure reliability using SOPM Proficiency of personnel Right technique for available reagents IQC EQA


POST ANALYTICAL FACTORS Accurate recording Range of normal values Age & sex related variation Turn around time Availability of guidance

Type of Laboratories : 

Type of Laboratories Small lab : deals with up to 50 pts./day Medium lab : 51-500 pts./day Large lab : >500 pts./day

Facilities at laboratory : 

Facilities at laboratory Separate space for - - sample collection sample analysis Storage of samples, reagents, chemicals, stationary, records, etc. Washing Media preparation Autoclaving Seminar room Library Staff room & toilets Adequate and qualified staff

Standard operating procedure manual (SOPM) : 

Standard operating procedure manual (SOPM) Each section of the laboratory should have a copy of SOP which should be easily accessible to all SOP should be available on the work bench area It should be reviewed annually SOP should contain only those procedures which are currently in use Any change in the SOP must be documented by recording it and having it duly signed by the Chief of the Laboratory

Essential components of SOPM : 

Essential components of SOPM Abbreviated administrative structure diagram Laboratory safety instructions Specimen collection Inoculation procedure Details of procedures Differential tests AST Serological testing Reference to higher laboratory Quality control Reporting


GENERAL RULES FOR COLLECTION AND TRANSPORT Apply strict aseptic techniques Wash hands before & after procedure Collection at optimum time specimen should be representative of infectious process & adequate in quantity Collect in appropriate sterile container Tightly close container Label the specimen & complete requisition form

Request Form : 

Request Form Patient’s name, age, gender, OPD no., ward Type & source of specimen, date & time of collection Investigation required Clinical note- suspected diagnosis & antibiotic history Name & signature of medical officer


CRITERIA FOR REJECTION OF SPECIMEN Missing or inadequate identification Insufficient quantity Specimen collection in an inappropriate container Contamination suspected Inappropriate transport or storage Unknown time delay Hemolysed blood sample


TRANSPORTATION OF SPECIMENS For short distance(by hand) specimen placed upright in appropriate racks For long distance  Placed in three containers Most specimens should be processed within 1-2hrs after collection




QUALITY CONTROL OF LABORATORY MATERIALS The reason for bad analysis is the poor quality of the following materials- a specimen that is not collected properly or preserved adequately Contaminated or deteriorated reagents glassware that is not properly cleaned a pipette that is not calibrated before use an instrument that is not calibrated or maintained properly.


PROPER USE OF REAGENTS AND STANDARDS Store all aqueous solutions in plastic bottles that can be tightly closed. Colored aqueous solutions are preferably stored in amber-colored plastic bottles. Never store organic liquids and solutions in plastic bottles. Keep all reagents and standards requiring refrigeration in the refrigerator. Never introduce a pipette, a glass rod, or any other substance into the reagent or standard bottle.


PIPETTE Inspect the pipette-right size, free of water spots, free of chipping. Introduce the pipette about 2 inches into the liquid. withdraw the liquid into the pipette to about 2 inches over the calibration mark. Empty the pipette slowly & Keep the pipette in the vertical position. At the end of the delivery, do not leave the tip of the pipette in contact with the liquid.

Quality control of equipments : 

Quality control of equipments

Slide 25: 


QUALITY CONTROL OF STAINS Each lot of newly prepared stain tested with positive & negative controls Regular testing done:  Weekly: Gram’s  Each use : Fluorescent  Each day of use: ZN stain & other stains Discard stains if outdated, deteriorated.




QUALITY CONTROL OF REAGENTS QC done with each new batch - daily for catalase, oxidase, coagulase tests - weekly for bacitracin, optochin, ONPG, X & V factors Mycobacteriology : each day of use Mycology: weekly with positive controls each new batch of serum for germ tube test Antisera: each new batch tested in parallel with previously tested batch using +ve & -ve controls Antigen detection kits: each day of use

Functional checks for equipments : 

Functional checks for equipments Calibration: process which is applied to quantitative measuring or metering of equipment to assure its accurate operation throughout its measuring limits Validation: steps taken to confirm and record the proper operation of equipment at a given point of time in the range in which tests are performed

Documentation : 

Documentation Name and serial number of instrument Elements to be checked and kind of data to be collected Frequency of checking Record of data Comments on data Changes made to restore accuracy & precision, if any Signature with date of the person performing these tasks

Quality control of Media : 

Quality control of Media Pivotal role in any micro lab used for isolation/identification & AST Various parameter for QC of media Raw material parameter Sterilization parameter Physical parameter Microbiological parameter a) Ecometric method b) Productivity ratio 5. Contamination parameter 6. Gel strength parameter

Raw material parameter (i)Water No Cu++ions conductivity(<15 microsiemens) pH(>5.5) (ii)Quality of petridishes - Eto toxicity(max permissible -1ug/g by standard chromatography methods) -glass petridishes (borosilicate) (iii)Blood- sterility,homogenecity,viscosity,colour.

Sterilization parameter Autoclaving time (to minimize heating damage) Quantity of media Indicators Temperature Pressure Physical parameters Bubbles/pits/unequal filling/cracks/freezing/pH

Microbiological parameters : 

Microbiological parameters Growth supporting characteristics(with both previous & new batch) Qualitatively Quantitatively

Slide 38: 

Organism inoculated in SCD broth for 4 hrs match with 0.5 McFarland col count of 1.5x108cfu/ml 10ul of inoculum-1 in 10 & 1in 100 diln in NS/SCD broth Selective media Nonselective media In duplicate Ecometric method and productive ratio give comparative data and therefore suitable for QC of media.

Ecometric method Based on Streaking of inoculum to extinction. AGI  RGI(AGItest/AGI controlx100,~100% for efficiency & ~0% for inhibition)

Productivity ratio- -Follow Modified miles & misra method( 10 fold diln of an overnight culture of test org. is made in PW) -Colony of lowest diln noted for both T & C -Productivity ratio(no.of col on test x diln factor/no. of col on controlx diln factor)

Contamination parameter : 

Contamination parameter Media autoclaved completely-incubate 2 plates-37c for 24hrs-contamination-incubate 2more plates-contamination-discard whole batch(Mackie –only 1 plate) Media containing non-sterilized additives e.g. blood,serum etc.-incubate entire batch for 24 hrs(Mackie-3days) - contamination exceeds >10%(WHO >3-5%) - discard the entire batch

Gel strength parameter -Indicate solidification of agar -By using a tripod stand with central rod to put pressure on agar wt. of central rod deducted while calculating gel strength Force=W/r2 W- weight kept on plateform. r- radius of spherical portion. 300-500 dynes/cm2  satisfactory


QUALITY CONTROL IN AST According to CLSI, Kirby Bauer method is recommended for antimicrobial testing by disc diffusion Standard strains Staphylococcus aureus ATCC 25923 Escherichia coli ATCC 25922 Pseudomonas aeruginosa ATCC 27853 Variables to be monitored: -Antibiotics potency(disc size 6mm) -Storage of discs (-200c) -Inoculums standardization(0.5McF) -Standard methodology -Incubation temperature( 350c) & time (16-18hrs) -Measure zone size precisely & interpret by referring to std. Charts

Factors influencing zone size in antibiotic susceptibility testing : 

Factors influencing zone size in antibiotic susceptibility testing

Slide 46: 

Perform testing for 30 consecutive days If >3/30 results outside accuracy limits yes No continuing daily testing Reduce testing to once per week until criteria satisfied all results in control limits No Yes daily testing for 5 consecutive days continue weekly testing all 5 results in Control limits No Yes resume daily testing for resume weekly testing consecutive days until satisfactory performance documented

Preservation of stock culture : 

Preservation of stock culture

Quality control in serology : 

Quality control in serology Most appropriate test must be chosen SOPM should be available all the time Hemolysed blood sample not suitable for serological tests sera to be used as controls should be kept sterile to avoid deterioration Each procedure should have -ve /+ve/borderline +ve controls

Levey-Jennings Chart : 

Levey-Jennings Chart A graphical method for displaying control results and evaluating whether a procedure is in-control or out-of-control Control values are plotted versus time Lines are drawn from point to point to accent any trends, shifts, or random excursions

Levey-Jennings Chart -Record and Evaluate the Control Values : 

Levey-Jennings Chart -Record and Evaluate the Control Values Mean Day +1SD +2SD +3SD -1SD -2SD -3SD

Findings Over Time : 

Findings Over Time Ideally should have control values clustered about the mean (+/-2 SD) with little variation in the upward or downward direction Imprecision = large amount of scatter about the mean. Usually caused by errors in technique Inaccuracy = may see as a trend or a shift, usually caused by change in the testing process Random error = no pattern. Usually poor technique, malfunctioning equipment

Accreditation : 

Accreditation Procedure by which an authorative body gives formal recognition that a lab is competent to carry out specific tasks Mandatory in developed countries, voluntary in India Require accreditation board(ISO,NABL), set of standards, inspectors/assessors Procedure: Application by labacknowledgement by NABL boardAssessorsassessment report to NABLFeedback to lab corrective measures by lab & reapplication to NABL approval & issue of accreditation certificate

Audit : 

Audit Planned & documented activity performed in accordance with written procedures & checklists to verify by investigation, examination & evaluation of objective evidence, that applicable elements of QA programme have been developed, documented and implemented. Internal audits: carried out by lab’s own staff

Preventive measures against laboratory-acquired infections : 

Preventive measures against laboratory-acquired infections Protect workers, patients and cultures Perform adequate sterilization before washing or disposing waste Provide safety hoods Ensure that tissues are handled and disposed of properly Promote regular hand washing and cleaning of bench Tops Ensure use of gloves Provide mechanical pipetting devices Protect patients from laboratory personnel with skin or upper respiratory tract infections Provide special disposal containers for needles and lancets

Slide 56: 


Staff & qualification : 

Staff & qualification Supervisory personnel small & medium lab- MBBS/MSc in concerned specialty with at least 5 year experience Large lab- MD/PhD in respective discipline Technical personnel Graduate in MLT Science graduate with 1 year experience in med. Size lab Diploma in MLT with 2 year experience in med.size lab

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