Oxalate Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Oxalate and links to relevant pages within the course.
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|Identify the urine sediment elements shown by the arrow:||View Page|
|Which one of the following crystals is not found in normal urine:||View Page|
|Which two of the following crystalline elements are found in acid urine:||View Page|
|Which of the following additives should be used for the collection of a sample for blood gas analysis:||View Page|
|Which of the following blood additives is most useful for serum collection:||View Page|
|Gray top tubes|
Contain an inhibitor of glycolysis, such as sodium fluoride.May also contain an anticoagulant such as potassium oxalate.
Used for accurate determination of glucose levels.
Blood may be collected into either:Red top (clot) tubes.Speckle top tubes (serum separator tube).Gray top tubes specifically designed to preserve glucose levels.
Gray top tubes contain additives such as sodium fluoride or potassium oxalate, which prevent metabolism of glucose by blood cells.
|Order of Draw|
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)
|Blood Collection Tubes|
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
|Common crystals which can be found in ACID urine include: (Choose all that apply.)||View Page|
|What are the microscopic elements that are indicated by arrows in this image?||View Page|
|What is the identification of these crystals seen in a urine with an acid pH?||View Page|
|What is the identification of these crystals seen in urine with an alkaline pH?||View Page|
Normal crystals include uric acid, calcium oxalate, amorphous urates or phosphates, triple phosphate, ammonium biurate, and calcium carbonate.
|Crystals in Normal Acid Urine|
Crystals found in normal acid urine include uric acid, calcium oxalate and amorphous urates. This slide shows an example of uric acid crystals.
|Crystals in Normal Alkaline Urine|
Crystals found in normal alkaline urine include triple phosphate, ammonium biurate, calcium carbonate, and amorphous phosphates. This slide shows an example of triple phosphate crystals. These may appear as four to six sided prisms resembling coffin lids. They indicate either stasis of the bladder or a stale sample.
|Calcium Oxalate Crystals|
Calcium oxalate crystals in their dihydrate form have a characteristic octahedral or envelope shape, as shown in the top image on the right. 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. In their monohydrate form, calcium oxalate crystals are dumbbell or oval in shape as shown in the bottom image on the right.
|Please identify these crystals.||View Page|
|Which of the following may be found in normal ACID urine?(Choose all that apply.)||View Page|
|Platelet satellites (see image to the right) may account for low platelet counts as determined by electronic counters. Satellitosis is initiated by:||View Page|