Calcium Information and Courses from MediaLab, Inc.

Antibodies have optimum temperatures for reactivity. Reaction readings can be made at different phases: after immediate spin, after incubation at 37°C, and after the addition of antihuman globulin (AHG) and centrifugation. Reactivity in a certain phase will help to determine whether the antibody is cold reacting (IgM) or warm reacting (IgG). It will also help to distinguish between antibodies that are clinically significant and not significant. Clinically significant antibodies that are capable of causing acute and delayed hemolytic transfusion reactions (HTR) or hemolytic disease of the newborn (HDN) are usually IgG and react best in the AHG phase.Readings can be done at all three phases if a tube method is used. If a gel method is used, readings are done only at AHG. Immediate spin: Antibodies reacting in this phase tend to be cold reactive. They are usually IgM class and not clinically significant (with the exception of the A and B antibodies). 37°: Antibodies that react in this phase include strong IgM or IgG antibodies. After incubation, the tubes are examined for the presence of hemolysis. If complement was bound during incubation then hemolysis could be seen. NOTE: This reaction would only occur in serum samples. If EDTA plasma samples are used for testing, the complement cascade has been halted. Magnesium and calcium ions are not available for complement to be activated. AHG:Antibodies reacting in this phase are considered clinically significant. They are usually warm reactive and IgG.

Kinetic Processes Specific to Platelets. Adhesion – When platelets adhere to exposed collagen, they take on a characteristic “spiny” shape. Their inherent stickiness, and the aforementioned spiny shape serve to compliment each other during this process. Von Willebrands Factor (vWF) is absorbed by surface receptors on both the platelet and exposed subendothelial tissue, thereby linking the platelets to the tissue. Release – This process occurs prior to aggregation. Platelets dump the contents of their granules (ADP, Serotonin, & Calcium), which aids the upcoming aggregation process by acting as a chemical signal. Aggregation – Platelets physically bind to each other, not just to the exposed subendothelial walls and collagen of the breached vessel. Platelet aggregation requires sufficient chemical signal stimulation. Stabilization (technically part of secondary hemostasis as fibrin is a product of secondary hemostasis)– This process strengthens the platelet plug with the addition of interwoven fibrin strands, ultimately producing a fibrin clot. The durable fibrin clot is the ultimate goal of hemostatic processes.

Then, activated factor IX (IXa), along with ionized calcium, platelet factor, and factor VIII, activate factor X, which is a direct precursor of thrombin in the common pathway. The activation of factor X signals the beginning of the common pathway. The activated partial thromboplastin time (APTT) is used to monitor the intrinsic pathway and the effectiveness of heparin therapy.

Consists of an electrolyte panel, plus: Blood urea nitrogen (BUN), which a measure of renal function. Creatinine (Creat), which also measures renal function Glucose, the most important blood sugar, and Calcium. Run on serum or plasma

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

Normal crystals include uric acid, calcium oxalate, amorphous urates or phosphates, triple phosphate, ammonium biurate and calcium carbonate.

Crystals found in normal acid urine include uric acid, calcium oxalate and amorphous urates. This slide shows an example of uric acid crystals.

Calcium oxalate crystals have a characteristic octahedral or envelope shape. Fine focusing will cause the "x" to be refractile. Size may vary from extremely small to quite large. They are associated with diets high in oxalic acid or chemical toxicity. Occasionally calcium oxalate crystals are dumbbell or oval in shape.