The concentration of sodium (Na) in blood serum/plasma is determined by ion-specific electrode (ISE) technology that measures the physiologically important activity of sodium ions present in the aqueous (water) phase of plasma.  Two methods are available: direct ISE and indirect ISE. Direct ISE, which is employed in...

Disturbance of sodium balance is a common occurrence among hospitalized patients that can, if not identified and treated, cause significant morbidity; severe disturbance is potentially lethal. So estimation of plasma sodium concentration is one of the most frequently requested blood tests.  Historically, plasma sodium ...

Discussion of electrolyte disorders associated with diabetes is most usually confined to the abnormality of plasma/serum sodium and potassium concentrations that occur in the two acute, life-threatening, conditions of decompensated diabetes: diabetic ketoacidosis (DKA) and hyperosmolar non-ketotic coma (HNKC).   As a...

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...

http://erj.ersjournals.com/content/early/2014/10/16/09031936.00039214.full.pdf+html. Accessed Oct 2014. Arterial blood gas (ABG) analysis is clinically useful because it allows assessment of two vital interrelated physiological functions: pulmonary gas exchange and maintenance of blood pH (acid-base homeostasis)....

Human chorionic gonadptrophin (HCG) is a hormone composed of two dissimilar sub-units (a and b) that is normally only produced in measurable quantities by synctiotrophoblastic (placental) cells during pregnancy. Pregnancy testing is based on measurement of the concentration HCG in urine or blood serum.    Blood levels ...

D-dimer testing can combined with assessment of pretest probability be used to rule out VTE in patients with a sufficiently low pretest probability of VTE. Patients with a negative D-dimer result can be ruled out, while patients with a positive D-dimer result need to have imaging performed for confirmatory diagnosis. ...

This short review aims to put the diagnostic options provided by state-of-the-art POCT  technology into perspective with the clinical challenges faced by physicians treating patients presenting with acute dyspnea.  Natriuretic peptides, hemoglobin, D-dimers and venous blood gases play a key role in the early...

Sampling capillary blood from the fetal scalp during labor of pregnancy, in order to determine its pH, was introduced to obstetric care in the late 1960s.  Despite current skepticism surrounding its utility, most notably in the US, fetal-scalp blood sampling (FSBS) is still considered a useful fetal monitoring test...

Circulating concentrations of the hormone brain natriuretic peptide (BNP) and its precursor molecule, NT-proBNP are increased in those with heart failure. This has allowed a now established role for serum BNP and NT-proBNP testing in the investigation of patients presenting with shortness of breath, a cardinal symptom ...