If you’ve ever been to the doctor and had blood drawn, chances are they utilized a handy little device known as a diff counter to quickly estimate the proportions of different types of blood cells in your body. This proportion is very important because it often tells much about the health of the patient, especially if they have a compromised immune system making them vulnerable to opportunistic infection. By taking a sample of your blood and observing it in a diff counter, the health professional can physically count the number of each type of blood cell to extrapolate whether a particular type of blood cell is either low or high in the patient. This is called a ‘differential count’, the namesake of the device used to help estimate blood cell count. This is such a good indication of general health that blood tests are one of the most common laboratory tests performed to this day.
Basically, the body has three types of blood cells—erythrocytes (red blood cells), leukocytes (white blood cells), and platelets (the elements that help your blood clot when you are cut). If any one of these three pieces of our body’s puzzle is out of the normal range, chances are you may be at risk for infection, bleeding, drug toxicity, or a number of other serious medical problems. To help discover this early, your doctor may suggest having a full blood panel run, which involves calculating the patient’s blood count. As I mentioned earlier, this is where a diff counter would be employed. Then, after generating a rough percentage based on the blood sample that a phlebotomist would have already drawn, prepped, and sent off to the lab, this sample number would be extrapolated to generate a full blood count. This number would represent the absolute number of each type of blood cell within the patient’s body, and some devices can even recognize more specialized blood cells based on their shape!
To generate the differential count, there are both automated and manual methods of counting the blood sample. A diff counter can be either—LW Scientific's 10 Key Digital Diff Counter with LED display is new for 2013 and uses modern computerized technology for simple and accurate blood cell counts, alongside the older, manual LW Scientific 5 or 8 Key Differential Counter . The manual diff counter requires that the physician actually count each individual cell under a microscope, utilizing proportions to generate a rough total blood cell count, while the automated variety often do this on their own to a high degree of accuracy. As you can imagine, in the hectic, modern world, most laboratories prefer the automated, digital units for both their ease of use and accuracy.