ANALYTICAL PROCESS CONTROL QC for QUALITATIVE TESTS John Elliot PPTC, Wellington, NZ WHO Collaborating Centre

Laboratory Sections that use Qualitative Tests Microbiology Blood Transfusion Infectious Diseases Serology PPTC, Wellington, NZ

INTERNAL QUALITY CONTROL (IQC) IQC REFERS TO THE SET OF PROCEDURES UNDERTAKEN BY THE LABORATORY STAFF FOR THE CONTINUOUS AND IMMEDIATE MONITORING OF LABORATORY WORK IN ORDER TO DECIDE WHETHER THE RESULTS ARE RELIABLE ENOUGH TO BE RELEASED. PPTC, Wellington, NZ

What is IQC? But does this apply to qualitative tests? The regular testing of quality control [QC] material along with the patient samples Comparison of the QC results to specific statistical limits [ranges] Rejection of patient results if QC is outside of limits But does this apply to qualitative tests? If not, Why not? PPTC, Wellington, NZ

WHAT IS THE MOST COMMON LABORATORY ERROR? TRANSCRIPTION Not technical PPTC, Wellington, NZ

Microbiology Quality Control Accuracy and clinical value of results depend on: Quality of specimen Validity of test method Performance of test procedure, reagents and media Reports and interpretation Staff Equipment PPTC, Wellington, NZ

In Microbiology how do we QC The Quality of the specimen The Performance of test procedures, reagents and media PPTC, Wellington, NZ

Specimen Appropriate specimen Collection method Delivery system PPTC, Wellington, NZ

Gram Stain PPTC, Wellington, NZ

PPTC, Wellington, NZ

PPTC, Wellington, NZ

IDENTIFICATION SYSTEM PPTC, Wellington, NZ

Specimen Processing: Test Methods Staining and Microscopy Culture Media Incubation Organism Identification Antimicrobial Susceptibility Testing PPTC, Wellington, NZ

Culture Media: Both Solid and Liquid Dating when received and when opened Weighing Dissolving Sterilizing Storage of prepared media Addition of enrichments [eg Blood] Sterility Testing Incubation of inoculated media PPTC, Wellington, NZ

QC of Media Agar Plates Liquid broths Therefore Stock Cultures Haemolysis controls Selective media controls Liquid broths Positive and negative reactions Therefore Stock Cultures PPTC, Wellington, NZ

Stock QC organisms Organisms to be maintained must be adequate to check all media and test systems. E. coli – MacConkey, XLD, susceptibility tests Staphylococcus aureus – Blood agar, Mannitol Salt, susceptibility tests Neisseria gonorrhoeae – chocolate, Thayer-Martin Discussion of where to get control organisms Discuss media used in their labs and what organisms should be used to test it. ATCC – best, but other sources may be available. May use known organisms from their lab and make stock cultures?? PPTC, Wellington, NZ

QC of Stains and Reagents Gram stain QC Use gram positive and gram negative organisms to check regularly [at least once a week] ZN QC Use positive and negative AFB slide with every batch stained. Other Stains Check as used – positive and negative reactions Reagents Check as used with known positives and negatives. PPTC, Wellington, NZ

Temperature Chart:Incubator PPTC, Wellington, NZ

Temperature Chart: Refrigerator PPTC, Wellington, NZ

Antimicrobial Susceptibility Testing Storage of antibiotic disks Correct concentration of antibiotic in disk Joan Stokes Method NCCLS Method Detailed QC Procedures to ensure reproducability of results Depth of agar!! PPTC, Wellington, NZ

Antimicrobial Susceptibility Testing PPTC, Wellington, NZ

Detecting Errors Many organisms have predictable antimicrobial test results Staphylococcus spp. are usually susceptible to vancomycin Streptococcus pyogenes are always susceptible to penicillin Klebsiella pneumoniae are resistant to ampicillin I think you could include a pretty long list here, that are worldwide in application. PPTC, Wellington, NZ

Sources of Error If you encounter an unusual pattern rule out error by checking identification of organisms repeat antimicrobial susceptibility test Report if repeat testing yields same result, or refer the isolate to a reference laboratory for confirmation Establish patterns in your patient population and advise health care providers. So providers can initiate treatment if necessary before susceptibility testing is complete PPTC, Wellington, NZ

QC in Blood Transfusion Service PPTC, Wellington, NZ

Blood Transfusion Service Blood Bank Hospital ? Donors Recipients Safety Precautions Recruit – Screen – Bleed test – process – Xmatch transfuse – follow up Policies Regulation FUNDING Government PPTC, Wellington, NZ

QC in Blood Bank Technology Donor services Blood grouping Crossmatch & antibody screening Transfusion PPTC, Wellington, NZ

QC in Blood Bank Positive and negative controls on all tests Reverse grouping Good documentation, SOPs etc Equipment monitoring, calibration, maintenance PPTC, Wellington, NZ

QC of Rapid Tests for Infectious Diseases PPTC, Wellington, NZ

Infectious Diseases Serology QC of Rapid Methods IQC Positive controls Negative controls How often? Where do you get the controls from? PPTC, Wellington, NZ

PPTC, Wellington, NZ

Qualitative vs.Quantitative Quantitative test measures the amount of a substance present Qualitative test determines whether the substance being tested for is present or absent Qualitative tests Tests that do not have measurable endpoints, for example: Growth-no growth Positive-negative Color change PPTC, Wellington, NZ

What is Quality Control? Process or system for monitoring the quality of laboratory testing, and the accuracy and precision of results Routinely collect and analyze data from every test run or procedure Allows for immediate corrective action PPTC, Wellington, NZ

Designing a QC Program – Establish written policies and procedures Corrective action procedures Train all staff Design forms Assure complete documentation and review PPTC, Wellington, NZ