I am a phlebotomist in a laboratory where my duties include venipuncture, specimen handling, and processing. During the verification process I used a drop of blood collected in an EDTA tube. Ethylenediaminetetraacetic Acid, or EDTA is an aminopolycarboxylic acid used as an anticoagulant in evacuated tubes. It inhibits the clotting process by removing calcium from the blood. High quality smears can be obtained from an EDTA blood sample within 2-3 hours. Attached are photos of a blood smear used under the Foldscope directly after a venipuncture. The magnification is not strong enough to distinguish individual cells as are the microscopes used by Hematologists, but at the low magnification you can see a separation of the cells to give a sandpaper like appearance. At the higher magnification is a cluster of red blood cells, still indistinguishable individually but at a closer look. I have just received a pack of glass slides that in the future I will use to look at different blood and body fluid samples.