QUALITY ASSURANCE
QUALITY ASSURANCE PROGRAM - A collective term which refers to the different methods used to assure reliable test results. - It encompasses comprehensive concepts , including components of Quality Control, which are primarily quantitative and statistical tools, and those aspects of laboratory management that impart perceptions of credibility and medically useful to clinicians. - The goal of Quality Control is to reduce both systematic and random errors. - In Japan, they refer to it as ZERO DEFECT

Importance of QC in patient care

-It serves as a foundation for a comprehensive program of assuring HIGH-QUALITY PATIENT CARE.

-The Joint Commission on Accreditation of Healthcare Organizations (JCAHO) defines Quality Control as a well-defined, organized program designed to enhance patient care through the ongoing objective assessment of important aspects of patient care and the correction of identified problems.

Quality Assurance Program
A. Pre-analytic al phase Test ordering, specimen collection, specimen transport and processing, patient information system. B. Analytical phase Specimen analysis, use of controls, record keeping C. Post-analytical phase Reporting of results, physician contact, reference ranges

Variability (errors) - RANDOM ERRORS – indeterminate errors which are a result of chance and sampling errors. They do not generally affect an entire batch of samples and therefore cannot be detected by testing control samples. They include personal or operator errors. - SYSTEMATIC ERRORS – determinate errors and sometimes referred to as BIAS. It affect all determinations in a batch equally and usually can be detected by testing control specimens. These errors are attributable to causes other than chance. It may include deteriorating reagents and improperly calibrated instruments.

Assessment of the quality of laboratory measurements
*PRECISION – describes how closely together repeat measurements of the same substance in the sample fall. It is synonymous with REPEATABILITY or REPRODUCIBILITY.
*ACCURACY – refers to how closely the measurement approaches the true value of the substance being analyzed. It is synonymous with CORRECTNESS

SPECIFICITY
-It means how good a test is at detecting only those individuals that have a disease as opposed to falsely labeling some healthy persons as having the disease.
-Technically, it means the specificity of a test reflects its ability to detect TRUE NEGATIVES with very few False positive results. TRUE NEGATIVES
SPECIFICITY= ----------------------------- TRUE + FALSE NEGATIVES POSITIVES

SENSITIVITY
-It means how well the test detects disease without missing some diseased individuals by falsely classifying them as healthy.
-It measures proportion of individuals with disease.
-Technically, sensitivity of a test indicates its ability to generate more TRUE POSITIVE results with few false negative results.

TRUE POSITIVES
SENSITIVITY= ----------------------------- TRUE + FALSE POSITIVES NEGATIVES

TO CONCLUDE:

WITH HIGH SPECIFICITY OF THE TEST IT WOULD MEAN ONLY THE PATIENTS WITH THAT DISEASE WILL DEMONSTRATE POSITIVE RESULTS.

THUS , WITH AN INCREASE IN FALSE POSITVE RESULTS WILL CAUSE A DECREASE IN SPECIFICITY
AND INCREASE IN FALSE NEGATIVE RESULTS WILL DIMINISH THE SENSITIVITY OF THE TEST.

CONTROLS
-Behave like the real sample or specimen tested in the laboratory.
-Available in a stable and sufficient quantity.
-Include a normal, high and low abnormal ranges (values).
-Preferably in a lyophilized state requiring reconstitution before use.
-They may be sourced out from 1.)Commercial control serum
( human serum or bovine-based products or 2.) Pooled control serum. The latter suffers from problems like deterioration, loss of potency and contamination risks.

Preventive measures for errors
| | |
|RANDOM ERRORS |SYSTEMATIC ERRORS |
|AWARENESS |USE OF QC PROGRAM |
| | |
|USE OF PROCEDURE MANUALS |INTERNAL / EXTERNAL |
| |LABORATORY MONITORING |
|INSTRUMENT MAINTENANCE | |
| |PREVENTIVE MAINTENANCE |
| | |
| |PERIODIC INSTRUMENT |
| |CALIBRATION |

QUALITY CONTROL MEASURES

ALWAYS RUN THE TESTS IN DUPLICATES.
USE OF MULTIVARIATE CHECKS. - Rule of Three ( Hemoglobin & hematocrit ) - Correlation of results - Comparison between Cell counts and blood smears

ALWAYS CHECK INSTRUMENT AND REAGENT PERFORMANCE ON REGULAR BASIS.

REPORT & APPLY NECESARRY CORRECTIVE AND PREVENTIVE MEASURES AS INDICATED

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