The portable device assist clinicians to count the number of CD4 cells and help doctors and patients in low-resource settings who do not have access to flow cytometers.

As a solution to this, Thomas Boland, a Professor of metallurgical, materials and biomedical engineering at University of Texas has created a less expensive, battery-powered health monitoring tool for use in third world countries.
The device is portable. It assists clinicians count the number of CD4 cells - cells that are attacked by HIV- in the body. The blood drawn is mixed with magnetic microscale beads that latch on to CD4 cells in the blood.
The mixture is placed in an inkjet printer that is modified to print out cells instead of ink. The cells are shot out horizontally onto a magnetized microscopic slide.
CD4 cells in the blood will be attached to the slide and the cells that do not need to be counted will dribble down into an excess container. Doctors can then look at the slide through a microscope to count the number of CD4 cells on it. The total number of CD4 cells in an individual’s body will be calculated using a equation. The procedure takes less than 20 minutes.
Source-Medindia