What is the main purpose of introducing reference change value in the laboratory?Group of answer choicesTo allow add-on tests to be added to the system automaticallyTo calculate the within-subject (CVI) and between subject (CVG) biological variationsTo facilitate establishment of personalised reference intervalsTo determine if the difference in two consecutive results is due to random variation

The main purpose of introducing reference change value (RCV) in the laboratory is to determine if the difference in two consecutive results is due to random variation.

Here's a step-by-step explanation:

1. The RCV is a statistical calculation used in laboratory medicine to determine if a significant change has occurred in consecutive measurements on the same subject.

2. It is calculated using the formula: RCV = Z x √2 x √(CVa2 + CVi2), where Z is the number of standard deviations appropriate to the probability, CVa is the analytical coefficient of variation, and CVi is the within-subject biological variation.

3. The RCV is used to compare two consecutive results from the same patient. If the difference between the two results is greater than the RCV, it is likely that the change is not due to random variation, but to a real change in the patient's status.

4. Therefore, the RCV helps clinicians to make more informed decisions about changes in a patient's health status, by distinguishing between random variation and significant change.