The term external quality assessment $($EQA$)$ is used to describe a method that

allows for comparison of a laboratory$$s testing to a source outside the laboratory.

This comparison can be made to the performance of a peer group of laboratories

or to the performance of a reference laboratory.

The term EQA is sometimes used interchangeably with proficiency testing;

however, EQA can also be carried out using other processes.

EQA is here defined as a system for objectively checking the laboratory$$s

performance using an external agency or facility.

Types of EQA Several EQA methods or processes are commonly used. These include:

$1.$ Proficiency testing$$external provider sends unknown samples for testing to

a set of laboratories, and the results of all laboratories are analyzed,

compared, and reported to the laboratories.

$2.$ Rechecking or retesting$$slides

that have been read are

rechecked by a reference

laboratory; samples that have

been analyzed are retested,

allowing for inter$-$laboratory

comparison.

$1$

External Quality Assessment $$ Module $10$ Content Sheet

$3.$ On$-$site evaluation$$usually done when it is difficult to conduct traditional

proficiency testing or to use the rechecking$/$retesting method.

Another method of inter$-$laboratory comparison is the exchange of samples

among a set of laboratories, usually reserved for specialized tests for which no

proficiency testing is available. This method is used either by very specialized or

sophisticated laboratories and therefore will not be further discussed in this

module.

EQA

benefits

Principal

characteristics

of an EQA

scheme

Participation in an external quality assessment program provides valuable data

and information which:

$$ allows comparison of performance and results among different test sites;

$$ provides early warning for systematic problems associated with kits or

operations;

$$ provides objective evidence of testing quality;

$$ indicates areas that need improvement;

$$ identifies training needs.

EQA helps to assure customers, such as physicians, patients, and health

authorities, that the laboratory can produce reliable results.

Individual laboratories can use EQA to identify problems in laboratory practices,

allowing for appropriate corrective action. EQA participation will help to

evaluate reliability of methods, materials, and equipment, and to evaluate and

monitor training impact.

For laboratories performing public health$-$related testing, EQA can help to assure

that results from different laboratories during surveillance activities are

comparable.

EQA participation is usually required for accreditation. Also, EQA participation

creates a network for communication, and can be a good tool for enhancing a

national laboratory network. Samples received for EQA testing, as well as the

information shared by the EQA provider, are useful for conducting continuing

education activities.

EQA programs vary but principal characteristics include the following:

$$ EQA programs can either be free$-$of$-$charge or require a fee. Free EQA

programs include those offered by a manufacturer to ensure equipment is

working correctly and those organized by a regional or national program for

quality improvement.

$2$

External Quality Assessment $$ Module $10$ Content Sheet

$$ Some EQA programs are obligatory, either required by an accrediting body or

by law. Others are voluntary, and the quality manager may choose to

voluntarily participate in an EQA program in order to achieve improvement

in the quality of the laboratory$$s performance.

$$ The EQA program can be organized at different levels: regional, national, or

international.

$$ Individual laboratory results are kept confidential, and generally are only

known by the participating laboratory and the EQA provider. A summary is

generally provided and allows comparison to the overall group.

$$ Some EQA schemes may

address a single disease,

for example the EQA

program for tuberculosis.

Others may address many

kinds of laboratory tests,

looking at the overall

testing performance for

microbiology. An example

of this multi$-$disease or test

program is the national

microbiology EQA in

France, which is

obligatory.

Successful performance in an EQA program reflects the effectiveness of the

laboratory$$s quality management, and allows for recognition of laboratory

quality by external groups.

EQA is important for improvement of the laboratory quality management

system, as it is a measure of laboratory performance.

$3$

External Quality Assessment $$ Module $10$ Content Sheet

Content Sheet $10-2$: Proficiency Testing

Definitions

Proficiency

testing

process

Roles of

laboratory

Proficiency testing, or PT$,$ has been in use by laboratories for many years. It is the

most commonly employed type of EQA, as it is able to address many laboratory

methods. List $10$ MCQ With answers