# Presentation: 079972

## QUALITY ASSURANCE OF TESTING OPERATIONS

**Thomas L. Hearn, Ph.D.**
**Deputy Director**
**Division of Laboratory Systems**
**Public Health Practice Program Office**

## Quality Assurance

**“****Planned and systematic activities to provide adequate confidence that requirements for quality will be met”  (ISO 8042, 3.4; NCCLS)**** **

## Class Exercise: Describe the Steps in a “Routine” Process

## T h e  W a l l

**T h e  W a l l**
**S t r e e t**
**J o u r n a l **
**Monday: February 2, 1987**
**“****Medical Labs, Trusted as**
**  ****Largely Being Error -Free,**
**  ****Are Far From Infallible”**

## Slide 5

## Benefits of Laboratory Quality Assurance

**QA provides evidence of good performance**
**Laboratory mistakes are prevented**
**Significant improvements in testing performance can be achieved* **
***Research findings from the College of American Pathologists, the University of Wisconsin, and the Centers for Disease Control and Prevention**

## Why Is Quality Assurance of Testing Important ?

**Public expects high quality**
**Defines parameters & quality goals**
**Evaluation & improvement system**
**Assures reliability & comparability of results**
**Cost effective**
**Even the simplest of testing is not foolproof  **

## Questions to Ask In Assessing a National QA System

**How is testing organized in-country?**
**Who makes testing policies?**
**Is there any central oversight?**
**Are laboratories required to have QA programs?**
**Which international agencies are, or were, active in technical assistance  **

## Questions to Ask In Assessing a National QA System

**How are decisions made about which tests can be used?**
**At the national level, who has authority & responsibility for QA?**
**What is the role of laboratory directors (national, provincial, and district) in QA?**
**How is training provided?**

## Quality Assurance

**“****Planned and systematic activities to provide adequate confidence that requirements for quality will be met”  (ISO 8042, 3.4; NCCLS)**** **

## Testing Process

- Analytic
- Specimen processing
- Specimen storage
- Reagent preparation
- Equipment checks
- Test performance

- Post-Analytic
- Results review
- Quality control review
- Report test results
- Results interpretation

- Pre-Analytic
- Test selection
- Patient instructions
- Test requisition
- Collect, label, transport specimen

## Quality Assurance Model

**U.S. Laboratory Regulations**

***P***

***T***

***Q***

***C***

**S****T****A****F****F**

## Quality Assurance (QA)

**Staffing / personnel**
**Quality control (QC)**
**Proficiency testing (PT) aka External quality assurance (EQA)**

## Staffing Components

**Able to execute responsibilities of director, supervisor, testing personnel**
**Appropriate educational credentials**
**Appropriate experience**
**Receive training**
**Competency assessments**

## Quality Control of theTesting Process

**Analytic**
**Specimen processing**
**Specimen storage**
**Reagent preparation**
**Equipment checks**
**Test performance**

- Post-Analytic
- Results review
- Quality control review
- Report test results
- Results interpretation

- Pre-Analytic
- Test selection
- Patient instructions
- Test requisition
- Collect, label, transport specimen
- Safety

## Pre-Analytic QC Components

**Safety**
**Specimen collection and handling**
**Test requisition and records**
**Referral for testing**

## Analytic QC Components

**Facilities**
**Test methods, equipments, reagents, supplies**
**Validation of test methods**
**Equipment checks**
**QC monitoring procedures**
**Procedure manual**

## Analytic QC Components

**Facilities**
**Test methods, equipments, reagents, supplies**
**Procedure manual**
**Validation of test methods**
**Equipment checks**
**QC monitoring procedures**

## Sensitivity, Specificity, and Prevalence

**If,**
**	**
**prevalence = 20%**
**sensitivity = 80%**
**specificity = 80% **
**Then,**
**predictive value of positive = **_**50%**_
**predictive value of a negative = **_**94.1%**_

**If,**
**	**
**prevalence = 20%**
**sensitivity = 99.9%**
**specificity = 99.9% **
**Then,**
**predictive value of positive = **_**99.6%**_
**predictive value of a negative = **_**100%**_

## Sensitivity, Specificity,

** ****and Prevalence**

**If,**
**	**
**prevalence = 0.15%**
**sensitivity = 95%**
**specificity = 95% **
**Then,**
**predictive value of positive = **_**2.8%**_
**predictive value of a negative = **_**100%**_

**If,**
**	**
**prevalence = 0.15%**
**sensitivity = 99.9%**
**specificity = 99.9% **
**Then,**
**predictive value of positive = **_**60%**_
**predictive value of a negative = **_**100%**_

## Analytic QC Components

**Facilities**
**Test methods, equipments, reagents, supplies**
**Procedure manual**
**Validation of test methods**
**Equipment checks**
**QC monitoring procedures**

## Slide 22

## Using Quality ControlReduces Error Rate

**  ****Sample HIV****	**** Number****	**** ****	****     ------------Errors-------------****	****    ****	****	**
**  **_**Ab Reactivity**_**	**** **_**Correct**__**	**__**	**__**With QC**__**	**__**	**__**Without QC**__**	**__**p-value**_
**  ****Negative****	****    6168****	****	****      3****	****   ****	****     19****	****	****  *****0.014***
**	**
**  ****Strong****	****   ****	****    4896****	****	****      4****	****     ****	****       3****	****	****  0.830**
**  ****Positive**
** **
**  ****Weak****	****	****    7021****	****	****  152****	****  ****	****   307****	****	****  *****0.0067***
**  ****Positive**
**  ****--------------------------------------------------------------------------------------------------------------------**
**  ****Total****	****	****  18085****	****	****   159****	****  ****	****   329****	****	****  *****0.0023***
**	****                ****(97.37%)****	****	****(2.20%)****	**** ****	****( 2.90%)**

**Source: Model Performance Evaluation Program, CDC**

**Using Quality Control****Reduces Error Rate**

## Post-Analytic QC Components

**Validation of test results**
**Reporting of test results**
**Interfacing to Laboratory Information Systems (LIS’s)**
**Corrective action plan**
**Records maintenance**

## Quality Assurance (QA)

**Staffing / Personnel**
**Quality control (QC)**
**Proficiency Testing / External Quality Assurance**

## Proficiency Testing or External Quality Assessment

**Central organization sends out challenge specimens for testing, laboratories’ results evaluated, laboratories sent scores**
**Split specimens exchanged with referral laboratories**
**Alternative methods**

## External Quality Assurance

**Early warning-system for problems**
**Measure of laboratory quality**
**Valuable benchmarking tool (standardization and traceability)**
**Indicator of where to direct improvement efforts**
**Monitor of changes in technology and testing practices (evaluation component)**

## Activities Linking

** ****QA Components**

**Assess personnel competencies**
**Assess pre-analytic, analytic, and post-analytic QC system**
**Assess PT/EQA performance**
**Implement communication systems for customers and staff, and systems for complaints investigations**

## Sources of Laboratory QA Guidance and Information

**World Health Organization (WHO)**
**UNAIDS**
**International Standards Organization (ISO)**
**NCCLS**
**CDC R&R’s**
**APHL recommendations**
**Professional  & accrediting organizations**
**United States laboratory regulations**

## If even the most conservative estimates of gains in improved testing quality are used, thousands of testing mistakes may be prevented yearly by laboratory quality assurance programs.

## Slide 31