Quality Assurance

define mean

the average value of a set of numbers

why is standard deviation useful

expresses how dispersed the data is from the mean, and is related to imprecision or random error

according to the Gaussian curve, approximately ___% of results are ±1 SD

68.3%

according to the Gaussian curve, approximately ___% of results are ±2 SD

95.5%

according to the Gaussian curve, approximately ___% of results are ±3 SD

99.7%

what is the purpose of the coefficient of variation

compares different sets of observations relative to the mean regardless of the unit

how is CV calculated?

CV = SD/mean x 100%

systematic error is related to

the y-intercept and the slope

changes in the y-intercept indicate _____ error

constant

changes in the slope indicate _____ error

proportional

random error is represented by

standard error of the estimate

what is the difference between primary standards and secondary standards?

• primary standards are extremely pure substances that have an exact known concentration and purity

• secondary standards are prepared in a lab to compare to primary standards to assure reference values are correct

analytical sensitivity is…?

the smallest amount of a substance within a sample that can be detected by a test

analytical specificity is…?

the ability of a test to detect only one type of substance and exclude others not of interest

how to calculate sensitivity

#of true positives / #of true positives x #of false negatives

how to calculate specificity

#of true negatives / #of true negatives x #of false positives

in regards to linear regression, the slope represents…?

how comparable results are across the range of linearity

what does the y-intercept represent

bias

what does the correlation coefficient represent

how well does the slope and y-intercept explain relationship

CMS

Center for Medicare (and Medicaid) Services

• responsible for enforcing CLIA 88

CLIA ‘88

Clinical Laboratory Improvement Amendments

• U.S. federal regulations that establish quality standards for all clinical laboratory testing performed on human specimens to ensure accuracy, reliability, and timeliness

what tests are classified as waived complexity

tests that require no certification or educational requirements for testing personnel

• rapid at-home tests (pregnancy, blood glucose monitors, urine dipsticks)

what tests are classified as moderate complexity

Automated analytical process with minimal manual steps required that are not defined as waived

• CBC, Automated chemistry, Microscopy

• requires proficiency testing, QC, and QA

what tests are classified as high complexity

Manual testing methodologies that require lab personnel with high level of training and expertise to perform accurately

• also needs QC, Continuous QA, and Proficiency Testing

• DNA & PCR testing

how is complexity determined

by the FDA