Analytical Testing Flashcards
What are a type of membrane that is selectively permeable to a single ionic species?
Ion-Selective Electrode (ISEs)
What are the two electrodes used in ISEs?
Reference Electrode (Constant Potential)
Measuring Electrode
What can the difference in potential be used for?
Measuring the concentration of the Ion in the solution
What is being measured in ISEs?
Activity of Ion
NOT concentration
What are the two types of ISE measurements?
Direct and Indirect methods
What is the Direct ISE measurement?
Undiluted sample to interact with membrane
What is the Indirect ISE measurement?
A diluted sample is used for measurement
What can we use for Na+ analysis?
Serum, Plasma, Whole blood, Sweat, Urine
What are the suitable anticoagulants when plasma is used for Na+?
Lithium Heparin
Ammonium Heparin
Lithium Oxalate
What is the specimen of choice for urine Na+?
24 hour collection
Why does hemolysis not cause significant errors in Na+ analysis?
RBCs contain only one tenth of Na+ present in plasma
What can we use for K+ analysis?
Serum, Plasma, Whole blood, Urine
Which tube is preferred for K+?
Heparin Anticoagulant
What can cause Artifactual Hyperkalemia?
Using the correct tube
Tourniquet left on too long
Patient clenches fist during collection
What is used in ISE measurements for K+?
Valinomycin Membrane
What do most analyzers use in ISE measurement for Na+?
Glass Ion-Exchange membrane
What can we use for Cl- analysis?
Serum, Plasma, Whole blood, Sweat, Urine
What tube should be used for Cl-?
Lithium Heparin Anticoagulant
What can be used to confirm the diagnosis of Cystic Fibrosis?
Analysis of sweat for increased Cl-
ISE’s, Amperometric-coulometric Titration, Mercurimetric titration, and Colorimetry can be used for what?
Analysis of Cl-
What is the sweat test for Cystic Fibrosis based on?
Pilocarpine Nitrate Iontophoresis Method
Sweat absorption
What can we use for HCO3- analysis?
Serum or Lithium Heparin Plasma
What methods do we use for the analysis of HCO3-?
Electrode or Enzymatic based
Indirect - Acidify - Measure pCO2
Enzymatic - Alkanize - Measure HCO3-
What is the Anion Gap in healthy individuals?
12mmol/L
Uremia/Renal failure, Ketoacidosis, and Diabetes are causes of what?
Elevated Anion Gap
Where do we see low Anion Gap values?
Hypoalbuminemia
Sever Hypercalcemia
