The gold standard sample for blood gas analysis is arterial blood, whereas venous blood is the standard sample for all other biochemical and hematological tests. By comparison with venipuncture, the procedure used to sample venous blood, collection of an arterial blood sample is technically more difficult, as well as...

A simple change in phlebotomy practice – switching from conventional to low-volume sample blood tubes – results in a 42 % reduction in patient blood loss, and consequent reduced risk of iatrogenic anemia. That is the positive headline finding of this recently published study conducted at the Royal Adelaide Hospital in ...

Thanks to KDIGO collaborative guidelines, diagnosis of acute kidney injury (AKI), defined as sudden decrease in kidney function (i.e. sudden decrease in glomerular filtration rate GFR), is simple and straight forwardly based on measurement of serum creatinine concentration and urine output. AKI is confirmed if any of...

In health plasma/serum potassium (K⁺) is maintained within the approximate reference range of 3.5 to 5.2 mmol/L, with serum values being slightly higher (∼ 0.4 mmol/L) than those of plasma because the process of blood clotting, essential to recovery of serum samples, is associated with release of potassium from...

Hemoglobin is the oxygen-carrying protein contained in red blood cells that ensures delivery of inspired oxygen from lungs to all tissue cells. This process depends on oxygen forming a reversible ionic link with ferrous iron (Fe⁺⁺) contained within the hemoglobin molecule. Methemoglobin (MetHb) is a dysfunctional form ...

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...

Because measurements of GFR are tedious, estimated GFRs based on creatinine or cystatin C are widely used for assessing kidney function. Both measured GFRs and the Staging System for CKD based on GFR have analytical and clinical shortcomings. The advantages of serum creatinine and cystatin C, and eGFR will be...