Bilirubin is a product of the hemoglobin catabolism that occurs principally in the spleen where red cells (that contain hemoglobin) are sequestered at the end of their approximate 120-day life. Bilirubin is transported in blood from the spleen to the liver where it is eliminated from the body in bile. Serum bilirubin...

In health total plasma calcium concentration is maintained within the approximate reference range of 8.8-10.5 mg/dL (2.20-2.62 mmol/L) so that raised plasma calcium (hypercalcemia) is usually diagnosed if plasma calcium is >10.5 mg/dL (>2.62 mmol/L) and severe, potentially life-threatening hypercalcemia is roughly...

In health, blood pH is maintained within a narrow reference range, 7.35-7.45.  Medical texts discussing general aspects of acid-base disturbance frequently include the observation that pH <6.8 is inevitably fatal. However, there are individual case reports of survival despite this degree of extreme acidosis. One such...

Reduced plasma/serum sodium (hyponatremia), widely defined as plasma/serum sodium Mild hyponatremia, i.e. plasma/serum sodium in the approximate range of 130 to 136 mmol/L, is usually not associated with symptoms, but most patients whose plasma/serum is Explanation of these effects of hyponatremia is contained in...

Almost all (99 %) of the approximate 1 kg of calcium in the adult human body is contained in bone, but a small fraction (approximately 350 mg) circulates in blood plasma at a concentration of around 2.5 mmol/L. This circulating calcium comprises three fractions: around half (50 %) is free ionized calcium; the rest is...

Blood gas analysis involves determination of three parameters (pH, bicarbonate and partial pressure of carbon dioxide, pCO₂) necessary for assessment of patient acid-base status and identification of those whose acid-base is disturbed. There are four classes of acid-base disturbance: metabolic acidosis, metabolic...

As the authors of this recently published review article acknowledge, sepsis is an increasingly common and serious illness that takes the lives of close to a third of those affected. Optimal care of patients with sepsis is delivered in an intensive care unit but rapid early diagnosis, vital for survival, occurs...

The process of laboratory/point-of-care testing of patient samples comprises three distinct phases: the preanalytical phase, which includes sample collection and transport to the site of testing; the analytical phase; and the postanalytical phase, which includes communication and interpretation of the test result as...

Plasma sodium concentration is normally maintained within the approximate reference range of 135-145 mmol/L. Raised plasma sodium (hypernatremia) is less common than reduced plasma sodium (hyponatremia), and severe hypernatremia (usually defined as plasma sodium >160 mmol/L) is rare but associated with potential for...

Intravenous (iv) catheters are routinely employed for speedy delivery of fluids and drugs to the critically ill; they also provide the means for sampling blood for testing. This iv catheterization occurs in a range of settings including prehospital emergency care, hospital emergency rooms and intensive/critical care...