Hemoconcentration

Hemoconcentration is the rise in cellular and protein concentration in the blood due to loss of blood plasma. This can be effected by many things including exercise. The loss of plasma in exercise can be atrributed to two things:

1. Increased blood pressure causes an increase in hydrostatic pressure in the capillaries thus forcing plasma from vasculture to intestinal compartment.

2.As metabolic waste products rise in the active muscles, intramuscular osmotic pressure increases wich attracts fluid to te muscles.

A prolonged tourniquet time may lead to blood pooling at the venipuncture site, a condition called hemoconcentration.Hemoconcentration can cause falsely elevated results for glucose, potassium, and protein-based analytes such as cholesterol.

Ideally, the tourniquet should be in place no longer than one minute to prevent hemoconcentration. If the phlebotomist takes longer than one minute to assess and locate vein of choice for venipuncture, it is best practice to release the tourniquet, assemble supplies and reapply tourniquet immediately before needle insertion.

Hemoconcentration: An increased concentration of larger molecules and formed elements in the blood may be due to several factors:

·         Prolonged tourniquet application (no more than 1 minute)

·         Massaging, squeezing, or probing a site

·         Long-term IV therapy

·         Sclerosed or occluded veins

Prolonged Tourniquet Application:

·         Primary effect is hemoconcentration of non-filterable elements (i.e. proteins). The hydrostatic pressure causes some water and filterable elements to leave the extracellular space.

·         Significant increases can be found in total protein, aspartate aminotransferase (AST), total lipids, cholesterol, iron

·         Affects packed cell volume and other cellular elements