Introduction Point-of-care testing (POCT) is now common in many near-patient and critical care settings. For blood gas and electrolyte testing, this includes operating rooms (ORs), intensive care units (ICUs), cardiac catheterization labs (CCL), emergency departments (ED), and many primary care…
Routine daily quality control on blood gas instruments Most current blood gas/electrolyte/metabolite analyzers have onboard internal quality control (QC) systems that automatically monitor the stability and performance of reagents, electrodes, and electronics of the analyzer. These control systems make these…
Sources of preanalytical errors in blood gas and electrolyte testing Introduction There are numerous sources of preanalytical errors in laboratory testing. Among these are the following: Wrong test ordered Wrong patient collected Error in sample collection, including improper patient preparation…
Introduction By 1900, many physicians had noted metabolic acidosis in patients who were critically ill. In 1925, Clausen identified increased lactate along with acidosis in these patients, which gave rise to the condition of “lactic acidosis,” although later work showed…
Osmolality and volume regulation Introduction Osmolality in plasma is related to the number of solutes (soluble particles) dissolved in a kg of plasma water, with a normal osmolality between 280 and 295 mOsm Measurement of serum osmolality is used to…
Introduction Symptoms of phosphate depletion have been described through the years, from the times of the ancient Romans to observations by veterinarians on livestock. Phosphate compounds are in all cells and participate in numerous biochemical processes. Phosphate is a component…
Introduction In 1695, from well water in Epsom, England, Dr. Nehemiah Grew prepared Epsom salts, a name still given to magnesium sulfate. The biological significance of magnesium as a constituent of plants has been known since the 18th century, with…
Introduction and history In 1883, Sydney Ringer showed that calcium was essential for myocardial contraction ( ) . In 1934, Franklin McLean and Baird Hastings published a report in the Journal of Biological Chemistry showing that the ionized calcium concentration…
Introduction Hypoxemia, a decreased partial pressure of oxygen in the blood, is a commonly encountered clinical problem among patients with acute or chronic cardiopulmonary disorders. Accurately characterizing the cause and severity of hypoxemia in a timely manner can have significant…
Physiologic differences between arterial and venous blood for blood gas and acid–base measurements More than any other analytes, p O 2 , p CO 2 , and pH change markedly from arterial to venous blood. While the pH apparently changes…