In health no more than 1-2 % of total hemoglobin is present as methemoglobin. This is a dysfunctional form of hemoglobin that is unable to bind and transport oxygen because the iron atom of the heme moiety is in the ferrous rather then the normal ferric state. Abnormal increase in methemoglobin, a condition called...

Part 2: Red flags The transition from fetus to newborn is a process of rapid physiological adaptation that is sometimes delayed by complications. Most newborns complete the process of transition with little or no delay.  These infants may demonstrate normal transitional findings, including tachypnea and tachycardia, ...

Tartu University Hospital has improved the quality of blood gas testing in its clinical laboratory and critical care units by introducing an automatic system for blood gas analysis [1].

Homeostatic mechanisms ensure that in health the extracellular fluid (ECF) concentration of electrolytes, including calcium, is maintained within well-defined limits. Abnormality in ECF calcium concentration can have profound adverse effects.  The most common means of assessing calcium status is to measure total...

Results of hemoglobin (Hb) and hematocrit (Hct) measurement are routinely used to assess blood loss among trauma patients. But is it necessary to measure both parameters and if not, is one more reliable than the other? There is evidence to suggest that many physicians believe hematocrit is a more sensitive indicator...

Modern blood gas analyzers often have incorporated technology that allows hemoglobin measurement on the same blood sample used to measure pH, pCO₂ and pO₂. Clinicians working in a UK neonatal intensive care department where such an instrument was routinely used for blood gases were keen to exploit the newly available...

Blood gas analysis of umbilical cord blood provides the means for establishing the acid-base status of babies at the time of birth. If there is to be any delay in sampling, the portion of cord from which the sample is to be taken should be double-clamped and thereby isolated from the placenta.  Previous studies have...

Measurement of blood lactate provides clinicians with a valuable means of identifying and monitoring critically ill patients who are suffering clinical shock as a result of severe trauma, sepsis or cardiogenic shock. Lactic acid accumulates in the blood of these patients due to the tissue hypoxia that results from...

Carboxyhemoglobin (COHb) is the product of the reaction between hemoglobin and carbon monoxide, and measurement of COHb is used in the diagnosis of carbon monoxide poisoning. Since carbon monoxide is a common pollutant present in cigarette smoke and car exhaust, it is difficult to be too dogmatic about what...

This is the second of two articles about the risks and benefits of red-cell transfusion directed at healthcare professionals without any particular transfusion expertise. The focus of the first article was the risks and the extensive measures taken to minimize those risks. For this second article, attention turns to...