3 Reference Interval Studies

Question 1

_______________ are used primarily for medical diagnosis. It is also used for assessment of physiologic function and for therapy management of patients. When interpreting laboratory results, physicians compare the measured test results of a patient with a reference interval.

Answer 1

Laboratory test results

Question 2

__________________ include all the data points that define the range of observations usually to define a specified percentage of values for a population. These are usual values
for a healthy population , commonly the central 95% of the population of interest.

_________________ are sometimes wrongly referred to as “normal values or ranges”

Answer 2

Reference intervals; Reference intervals

Question 3

Reference intervals are sometimes called _____________, the former is preferred because range implies an absolute minimum and maximum values.

Answer 3

reference ranges

Question 4

_________________ are usually established by the scientific community or the manufacturers of reagents and new methodologies

Answer 4

Reference intervals

Question 5

Presence of ______ and ______-stratified normal values for all populations tested.

The clinical laboratory is required by good laboratory practice and accreditation agencies to either verify or establish reference intervals for any new tests or significant changes in methodologies.

Answer 5

age; sex

Question 6

A new reference interval is established when there is no existing analyte or methodology in the clinical or reference laboratory with which to conduct comparative studies. It is a costly and labor intensive study that will involve laboratory resources at all levels and may require from 120 to as many as 700 study individuals. The minimum requirement of 120 subjects are from each age and sex
group.

Answer 6

Establishment of a Reference Interval

Question 7

This is done to confirm the validity of an existing reference interval (commonly published by manufacturers) for an analyte using the same type of analytic system, method or instrument. These are the most common reference interval studies performed in the clinical laboratory and can require as few as 20 study individuals. When two or less than two values fall outside the suggested interval, the manufacturer’s reference interval is accepted. However, if there are more than two values falling outside the suggested interval, a second testing will be required. The second testing will require another 20 subjects. In the second testing, two or less than two falling outside the interval means acceptance of the manufacturer’s established reference interval. More than two values outside the interval requires a complete study which requires a study using 120 subjects.

Answer 7

Verification of a Refence Interval (Transference)

Question 8

___________ samples should not be used for reference interval studies that are designed to reflect a population

Answer 8

Inpatient