This second of two articles on understanding the clinical value of measuring urea concentration explores the clinical value of simultaneous measurement of urea and creatinine and calculating the urea:creatinine ratio. The article discusses the causes of increased and decreased ratio as well as the clinical application ...

This first of two articles on understanding the clinical value of measuring urea concentration dives into the physiological topics, such as urea production and renal processing of urea as well as the causes of increased and reduced urea concentration. Kidney disease is associated with reduced urea excretion and...

The maintenance of blood pH within normal limits (7.35-7.45), called acid-base homeostasis, is a complex synergy involving three organs (lungs, kidneys and brain) as well as chemical buffers in blood and blood cells (erythrocytes). This vital physiologic process is the subject of a recent expert review article,...

Glomerular filtration rate (GFR) is a parameter of prime clinical significance because it defines kidney function. All those with reduced kidney function, no matter what the cause, have reduced GFR, and GFR correlates well with disease severity. The most accurate assessment of GFR is thus valuable not only for early...

The necessary administration of image-enhancing agents to patients prior to radiological investigation is associated with risk of two serious adverse effects: nephrogenic systemic fibrosis (NSF) and contrast-induced nephropathy (CIN). The risk only applies to those patients with renal disease, either acute kidney...

Anemia, which is defined as hemoglobin (Hb) concentration The kidneys are essential to the regulation of red-cell production and thereby maintenance of normal Hb concentration because the hormone erythropoietin, which regulates red-cell production, is synthesized in the kidneys. The usually normochromic, normocytic...

Hemodialysis and related treatments for those with failing kidneys all involve blood flow through a circuit outside the body. This extracorporeal circuit - the dialysis machine and its connections from and back to the body - is a non-physiological, pro-coagulant environment.  To counter the tendency for patients'...

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...

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...