Hemoglobin is the oxygen-carrying protein contained in red blood cells (erythrocytes). Although normally present in only trace amounts, there are three species of hemoglobin that cannot transport oxygen.  The three species, collectively called dyshemoglobins because of their functional redundancy, are methemoglobin,...

Methods for the measurement of hemoglobin (Hb) were first developed well over a century ago, so that hemoglobin was among the first diagnostic blood tests available to clinicians during the first decades of the 20th century when laboratory medicine was in its infancy.  Today it is the most frequently requested blood...

The significance of good practice during the pretesting phase of clinical laboratory investigation cannot be overemphasized. The production of high-quality, accurate results, which are clinically useful, depends as much on practice before the patient’s sample reaches the laboratory as it does on the analytical phase...

Disturbance of the mechanisms which maintain normal blood pH is a defining feature of diabetic ketoacidosis (DKA), an acute and life-threatening complication of the chronic metabolic disease, diabetes.  For this reason diagnosis and monitoring of DKA invariably include measurement of arterial blood gases. This...

Arterial blood gas analysis is a test most frequently performed on critically ill patients in the emergency room, recovery room and intensive care unit by nursing staff. One of the main purposes of the test is assessment of acid-base status, which is often disturbed during critical illness. This article is intended...

Non-invasive monitoring of oxygenation has become a standard procedure in neonatal critical care. Both transcutaneous pO₂ (tcpO₂) monitors and pulse oximeters involve methodological and practical issues that should be known to those using these devices in infants. tcpO₂ measurements are influenced by skin thickness, ...