The process of patient sample testing, whether performed in the clinical laboratory or at the point of care, is the sum of three distinct phases. The first is the preanalytical phase, which includes test selection as well as sample collection and handling.  The second is the analytical or measuring phase that...

Metformin, a blood-glucose-lowering drug widely used for treatment of type 2 diabetes, is associated with risk of potentially fatal metabolic (lactic) acidosis. This can occur not only following overdose but also at therapeutic dose in patients with pre-existing renal or liver disease. Results of arterial blood gas...

BACKGROUND: Besides actual pH, base excess (ctH⁺_B (mmol/L)) is of major importance since it is meant to reflect lactate acidosis due to fetal hypoxia; in vivo BE_B is not independent from pCO₂. Independence is achieved by using the extended extracellular fluid (Ecf) for dilution of hemoglobin (cHb_B), reducing cHb_B to ...

Some of the frequently asked questions are: Should we use BE (base excess) or SID (strong ion difference) as a measure of a metabolic acid-base disturbance?  Is there any difference between BB (buffer base) and SID? Should we use SBE (standard base excess), i.e. BE referring to the expanded extracellular fluid or...

Although measurement of serum lactate has an established role in the monitoring of critically ill patients at many hospitals around the world, the practice is by no means universal, reflecting a controversy that still surrounds the topic. In short there remains no consensual answer to the broad question: Should we...

Pleural effusion, defined as excess fluid in the pleural space, can complicate the course of a large and pathologically diverse range of pulmonary and non-pulmonary diseases. Laboratory analysis of pleural fluid provides much useful information for the clinician whose diagnostic challenge is the patient presenting...

The anion gap (AG) is a calculated parameter derived from measured serum/plasma electrolyte concentrations. The clinical value of this calculated parameter is the main focus of this article. Both increased and reduced anion gap have clinical significance, but the deviation from normal that has most clinical...

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...

Metabolic acidosis is the most common disturbance of acid-base balance among the critically ill of all ages, usually due to increased lactate production consequent on inadequate tissue perfusion and/or hypoxemia. The condition is characterized by primary reduction in bicarbonate and pH revealed during arterial blood...

Umbilical cord blood gas analysis provides objective evidence of neonatal condition at birth; a particular utility of the test is to identify those babies who have suffered significant oxygen deficit prior to delivery. Traditional obstetric practice is to clamp the umbilical cord within seconds of delivery but some...