Merimac

The automatic counts are vaery good for counting numbers of cells accurately. A manual count is good for inspecting the size of cells, the shape of the cells and distinguishing similar cells apart. Since the computer is designed to count similar shapes and color, unless it is programmed to do something differently, an automated count will tell exactly how many of what type of cells are abnormally large or small even if they are the same size as a normal cell. If there is anything at all wrong with the numbers, a manual count should be done to ensure accuracy. An automated count is convenient but can have a large margin of error in platelet counts because of them sticking together(think of a new package of computer printing paper.)
As we get into the new technology age in medicine, fewer people even know how to do an accurate manual count, and are relying on the computer to spot the unusual so that all the tech has to do is look at what the computer says in unusual. Last thing to remember is that although it seems like the lab tech takes a lot of blood, it is really just enough to do all the tests the doctor orders, and to repeat them if the lab has an accidental spill, or the lab is not satisfied with your results. If they report an unusual finding, the doctor generally orders a fresh sample to see if the results are still showing the same thing. Most of the blood cell counts will change up or down somewhat from one draw to the next because of the dynamics of living.