Transitory hyperglycemia (raised blood glucose) is a common feature of critical illness that was once viewed as a benign effect that could be safely left untreated, unless it was particularly severe.  This traditional attitude to hyperglycemia in the critically ill changed dramatically in 2001 with the publication of...

The discriminative ability of a diagnostic procedure is called diagnostic accuracy, and a number of quantitative measures out of which sensitivity and specificity are mostly used in the biomedical literature can express it. Each diagnostic-accuracy measure relates to some specific aspects of a diagnostic procedure....

The field of point-of-care testing (POCT) is entering a period of rapid expansion. This expansion is being driven by new evidence for clinical effectiveness of POCT, and new technologies that allow consolidation of testing onto smaller platforms. Technological improvements will also lead to increased accuracy for...

Recent studies of D-dimer as a “rule-out” test for deep venous thrombosis (DVT) frequently have used duplex ultrasound rather than venography as the gold standard. Because duplex ultrasound has limited ability to image the calf veins, there is potential for ultrasound studies to classify patients with calf DVT as...

Patients with heart failure (HF) experience significant morbidity and mortality and those admitted for acute decompensated HF are at particularly high risk for adverse events. Hospitalization represents the major component of the high cost associated with the management of patients with HF. Accordingly, early and...

The lowest ever recorded arterial oxygen tension (pO₂) was just one result of a series of remarkable physiological investigations conducted on Mount Everest that included arterial blood gas analysis at an altitude of 8,400 m (27,599 ft) above sea level, just 484 m short of the summit.  At this high altitude the...

The notion that increased oxygen delivery limits ischemic damage to the myocardium during myocardial infarction seems, on the face of it, highly plausible. Perhaps not surprising, then, that for the best part of a century administration of oxygen has been a routine component of medical care for many patients suffering ...

 Of all tests performed on patient blood samples, arterial blood gases (ABGs) are conceptually probably the most complex. An understanding of the clinical significance of the measured and derived parameters generated by blood gas machines depends on a basic knowledge of so many topics, including acid-base theory,...

Premature neonates frequently have inadequate respiratory function and require oxygen therapy during the weeks after birth. Since they are also exquisitely vulnerable to oxygen toxicity, careful monitoring of oxygen status is an essential component of neonatal intensive care.  Measuring % oxygen saturation by pulse...

Hemolysis, the breakdown of erythrocyte (red-cell) membranes, can occur in vivo as a result of disease, or more commonly in vitro when it is most usually a consequence of poor blood collection or sample handling technique.  Hemolysis is of significance for laboratory staff because it results in the release of...