Potassium Information and Courses from MediaLab, Inc.

The following table lists some of the chemicals present in CSF, and their concentrations: ChemicalLevel sodium 136.0 - 150.0 m Eq/L potassium 2.3 - 2.7 m Eq/L magnesium2.4 - 3.0 m Eq/Lprotein2 - 4 mg/dL (normally diffuses across blood-brain barrier) glucose 45.0 - 60.0 mg/dL calcium2.1 - 2.7 m Eq/dLcholesterolpresent in small amounts creatinine 0.5 - 1.2 mg/dL lactic acid dehyrdogenase (LDH) present in small amounts phosphorus (inorganic)1.0 - 2.0 mg/dLurea6.0 - 16.0 mg/dL uric acid 0.5 - 3.0 mg/dL

False negative results occur when elements present in the urine interfere with either the enzymatic reaction or prevent the oxidation of potassium iodide. Examples of such substances include: large quantities of ketones aspirin ascorbic acid > 50 mg/dL with some reagent strips levadopa 5-hydroxyindoleacetic acid homogentisic acid sodium fluoride ( a preservative)A specific gravity higher than 1.020 may lower glucose reagent sensitivity, especially in the presence of a high urine pH. Exposing reagent strips to excess humidity may also reduce glucose reagent reactivity.Check the package insert of the reagent strips used in your laboratory for interfering substances that may affect glucose results.

Marcie Moore was a phlebotomist at a community hospital in Atlanta. It was her week to collect the pediatric unit and she was on her way to the room of a newborn for which she had just received orders to draw a STAT BMP (chem-7) and bilirubin. After informing the mother of the baby about the test she needed to perform, Marcie set up to perform a heel stick on the baby. Marcie chose a site on the outer edge of the heel on the bottom of the baby’s foot ( the correct area for a heel stick) and made a small incision with a Tenderfoot lancet after cleaning the site well with alcohol.She immediately began collecting the blood in the correct tube for the BMP and bilirubin. Blood flow was not strong so Marcie squeezed the baby’s foot a little to help the blood come out faster – the newborn was screaming and Marcie could tell it was making the mother uncomfortable. She wanted to hurry and get done so the mother could hold the baby.After the chemistry tech ran the blood tests on the tube, she informed Marcie that the newborn had a panic potassium level which did not coincide with the previous blood work on the newborn. Also the chemistry instrument could not perform the bilirubin due to hemolysis. Marcie was asked to recollect the specimen.

Blood is tested for the most important electrolytes (salts): Sodium (Na) Potassium (K) Chloride (Cl) Carbon dioxide (CO2)Can be run on serum or plasma.

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.