Beta-2 microglobulin is a protein found on the surface of many cells. Testing is done primarily when evaluating a person for certain kinds of cancer affecting white blood cells including chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and multiple myeloma or kidney disease. It is plentiful on the surface of white blood cells.

Betalactam antibiotics are the most widely used antibacterial drugs in practical medicine. It includes penicillin derivatives, cephalosporins, monobactams, carbapenems and ?-lactamase inhibitors. These are indicated for the prophylaxis and treatment of bacterial infections caused by susceptible organisms. These antibiotics all share three carbons, one nitrogen structure known as the beta-lactam ring. An intact beta-lactam ring is required for these antibiotics to exert its bactericidal activity.

Biaxial total wrist arthroplasty is a wrist prosthesis of an unconstrained design. It has a rounded articulating interface, orientated in the plane of movement of the wrist. It aims to achieve physiological movement by offsetting the radial component ulnar-wards and volar-wards, bringing the third metacarpal into line with the ulnar border of the radius with the axis of movement passing through the centre of rotation, the proximal pole of the capitate. Porous coating is applied to enhance bony ingrowth and fixation.

Bicanalicular lacrimal intubation system employs a guide wire approach to lacrimal intubation. A polypropylene thread attached to the silicone tubing is guided into the lacrimal duct using a specially designed grooved probe. Once the thread is in place, forceps are used to grasp and pull it from the nose. The thread is then used as a leader to pull the silicone tubing. The procedure is atraumatic and bloodless making it particularly attractive for use in children. This system is coated with a thin polyvinylpyrrolidone (PVP) coating that makes the surface slick as glass to prevent debris from collecting on the surface.

Bifocal contact lenses are designed to give good vision to people who have a condition called presbyopia. These are available in both soft and rigid gas permeable (GP) materials, and some can be worn on a disposable basis.

Bifocal lens is an uncoated, plastic lens that corrects both for distance and near vision in individuals with presbyopia. The top of the lens corrects for distance vision. In the lower part of the lens, there is a visible semicircle ground into the lens that corrects for near vision.