Which of the following might lead to unacceptable quality control results?

Question

Quizplus · Accepted Answer

All of the listed factors can lead to unacceptable quality control results. 
A technician who has not worked in the area for several months may not have the necessary skills and knowledge to perform the testing accurately. 
A deteriorated "Anti-A" can result in inaccurate results, as the reagent may not be effective at detecting the presence of the antigen. 
An uncalibrated serofuge can also produce inaccurate results, as the device may not be properly measuring or separating the components in the sample.

Which of the Following Might Lead to Unacceptable Quality Control