Lithium Information and Courses from MediaLab, Inc.

The order of draw for a capillary blood collection is slightly different than the order of draw for a venous blood collection.If capillary blood gases are ordered, they are drawn first to avoid introduction of room air as much as possible. A specimen for blood count is collected before tubes containing other anticoagulants and additives. This is to ensure that the blood will not begin to clot before this specimen is collected; clots will affect the accuracy of the blood count. The following order of draw is commonly used: Container Additive Use Lavender top EDTA For hematology blood counts Green top Lithium heparin Tests that require a heparinized plasma sample __ Other tubes containing anticoagulants Varied Red or gold top Clot activator Tests that require a serum sample Red top No additive Tests that require a serum sample but clot activator and/or gel may affect test

Contain either sodium or lithium heparin.Used for tests requiring whole blood or plasma such as ammonia or whole blood potassium.

Blood collection tubes must be filled in a specific order to avoid specimen contamination from the additive in the preceding tube. The following order of draw is an accepted laboratory standard. 1. Tubes or bottles for blood cultures 2. Light-blue top tubes (sodium citrate) 3. Serum tubes (with or without clot activator) 4. Green top tubes (sodium or lithium heparin) 5. Lavender or pink top tubes (Potassium EDTA) 6. Gray (Sodium fluoride and sodium or potassium oxalate)

Most blood collection tubes contain an additive that either accelerates clotting of the blood (clot activator) or prevents the blood from clotting (anticoagulant). A tube that contains a clot activator will produce a serum sample when the blood is separated by centrifugation and a tube that contains an anticoagulant will produce a plasma sample after centrifugation. Some tests require the use of serum, some require plasma, and other tests require anticoagulated whole blood. The table below lists the most commonly used blood collection tubes. Tube cap color Additive Function of Additive Common laboratory tests Light-blue 3.2% Sodium citrate Prevents blood from clotting by binding calcium Coagulation Red or gold (mottled or "tiger" top used with some tubes is not shown) Serum tube with or without clot activator or gel Clot activator promotes blood clotting with glass or silica particles. Gel separates serum from cells. Chemistry, serology, immunology Green Sodium or lithium heparin with or without gel Prevents clotting by inhibiting thrombin and thromboplastin Stat and routine chemistry Lavender or pink Potassium EDTA Prevents clotting by binding calcium Hematology and blood bank Gray Sodium fluoride, and sodium or potassium oxalate Fluoride inhibits glycolysis, and oxalate prevents clotting by precipitating calcium. Glucose (especially when testing will be delayed), blood alcohol, lactic acid

One of the steps in the H&E procedure is bluing. As the name implies, this step converts the initial soluble red color of the hematoxylin within the nucleus to an insoluble blue color. The alkaline pH of the bluing solution causes the mordant dye-lake to reform in the tissue and become more permanent. Some examples of bluing solutions include: Ammonia water Dilute lithium carbonate Scott's tap water (potassium carbonate, magnesium sulphate, and water)