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For example, the complete blood count can help a physician to determine why a patient feels unwell and what to do to help. Cell counts within liquid media (such as blood, plasma, lymph, or laboratory rinsate) are usually expressed as a number of cells per unit of volume, thus expressing a concentration (for example, 5,000 cells per milliliter).
Isotonic (of equal water potential)—this prevents water gain or loss by the organelles; Cool—reducing the overall activity of enzyme released later in the procedure; Centrifugation is the first step in most fractionations. Through low-speed centrifugation, cell debris may be removed, leaving a supernatant preserving the contents of the cell.
A laboratory centrifuge is a piece of laboratory equipment, driven by a motor, which spins liquid samples at high speed. There are various types of centrifuges, depending on the size and the sample capacity.
Perfusion may also refer to fixation via perfusion, used in histological studies. Perfusion is measured as the rate at which blood is delivered to tissue, [2] or volume of blood per unit time (blood flow) per unit tissue mass. The SI unit is m 3 /(s·kg) [citation needed], although for human organs perfusion is typically reported in ml/min/g. [3]
Typically, ten-fold dilutions are used, and the dilution series is plated in replicates of 2 or 3 over the chosen range of dilutions. Often 100 μL are plated but also larger amounts up to 1 mL are used. Higher plating volumes increase drying times but often do not result in higher accuracy, since additional dilution steps may be needed. [5]
The osmotic pressure of the plasma affects the mechanics of the circulation in several ways. An alteration of the osmotic pressure difference across the membrane of a blood cell causes a shift of water and a change of cell volume. The changes in shape and flexibility affect the mechanical properties of whole blood.
The silica particles are desiccants, which adsorb and hold water vapor. [3] This is used in the tubes so the blood adheres to the surface of the tiny silica particles and begins to clot. After the blood sample is centrifuged, the clear serum should be removed for testing. [4] [5]
These tubes are commonly sealed with a rubber stopper and often have a specific additive placed in the tube with the stopper color indicating the additive. For example, a blue-top tube is a 5 ml test tube containing sodium citrate as an anticoagulant, used to collect blood for coagulation and glucose-6-phosphate dehydrogenase testing. [5]