Melinda was working the day shift in the hematology laboratory. The laboratory’s protocol called for three levels of blood cell controls to be run at the following times: 1) at the beginning of the shift, 2) within each run of patient samples during the day and 3) any times reagents were changed. The mean for the low (abnormal) control for the red blood cell count was given as 2.00 x 10^12/L, the standard deviation was 0.15, and the confidence limit (acceptable control range) was 2.00 x 10^12/L +/- 2sd (or +/- 0.3). The first morning low control result was 2.10 (x 10^12/L). In five subsequent runs, the low control results were 2.16, 2.19, 2.20, 2.22 and 2.25. 1. Do these values represent a shift, a trend, or neither? 2. Should Melinda be concerned about these values? Explain. 3. Does Melinda need to take any action?

Melinda was working the day shift in the hematology laboratory. The laboratory’s protocol called for three levels of blood cell controls to be run at the following times: 1) at the beginning of the shift, 2) within each run of patient samples during the day and 3) any times reagents were changed. The mean for the low (abnormal) control for the red blood cell count was given as 2.00 x 10^12/L, the standard deviation was 0.15, and the confidence limit (acceptable control range) was 2.00 x 10^12/L +/- 2sd (or +/- 0.3). The first morning low control result was 2.10 (x 10^12/L). In five subsequent runs, the low control results were 2.16, 2.19, 2.20, 2.22 and 2.25. 1. Do these values represent a shift, a trend, or neither? 2. Should Melinda be concerned about these values? Explain. 3. Does Melinda need to take any action?