Quality Control

Within batch, between batch, external Each blood test result produced by an accredited laboratory will have quality control procedures in place to ensure that inevitable variations in machine, staff, and temperature do not affect the result. 

Within batch variation

This is used to evaluate how good the technique is at giving the same result for identical samples in one attempt. This method often identifies whether a machine has bias towards a certain location on the rotor. Figure 1.1 shows a typical rotor which has 11 samples ready to analyse. H and L are primary standards and each yellow circle represents the same sample in replicate With the results from the experiment we can calculate the mean and standard deviation (SD) of the 9 identical yellow samples. Using the mean and standard deviation we can calculate the %Coefficient of Variance (CV)= ((SD /Mean)x100). This data is used to create the Y-Axis of a control plot. A common misconception is that a low CV is by default better than a higher one. The most important thing is that to consider is if the CV changes.

Figure 1.1: Within batch variation