A method of determining blood viscosity of blood in the body. Venous pressure in a body vein is maintained at a constant pressure. Blood is then withdrawn from the vein at a constant pressure for a time period and the volume of blood withdrawn is determined, to obtain an indication of blood viscosity when in the body. The time period can be constant and the blood volume is then proportional to body blood viscosity. Alternately a predetermined volume of blood is withdrawn and the time period is measured and is proportional to blood viscosity in the body. Preferably a three-way valve is incorporated into a system comprising a needle, syringe and vacuum gauge to enable withdrawal of blood at a predetermined negative pressure so that blood viscosity can be obtained rapidly and inexpensively.

A wearable-type glucose sensor for continuously or intermittently determining the glucose content comprises a short hollow fiber (2) to be positioned in the subcutaneous tissue. This hollow fiber is connected via tubes (3,4) with component parts (5 . . . 12) located outside the body, such as a measuring unit (11). When a perfusion fluid containing the enzyme glucose oxidase is passed through the hollow fiber, a subcutaneous dialysis will take place in which some glucose dissolves in the perfusion fluid through the wall of the hollow fiber. This glucose is completely oxidized by the oxygen dissolved in the perfusion fluid in the presence of the glucose oxidase. By means of the measuring unit the resultant amount of H.sub.2 O.sub.2 or, preferably, the employed amount of O.sub.2 is determined, both of which are a measure of the subcutaneous glucose concentration.

A dynamic continuous flow enzyme reactor and method for carrying out and analyzing phospholipid-dependent enzyme reactions are provided. The enzyme reactor is a tubular member preferably a capillary tube, coated on its inner surface with a planar phospholipid bilayer membrane, optionally and preferably containing an enzyme or enzyme cofactor. The reactor is connectable at one end to a means for delivering fluid flow reagents to the reactor and is connectable at a second end to a means for analyzing an effluent exiting from the reactor. Preferably the enzyme cofactor in the phospholipid membrane is purified tissue factor and the fluid reagents are inactive blood clotting factors which become activated upon interaction with the phospholipid membrane through a tissue factor-mediated reaction.

A therapeutic composition suitable for extracorporeal treatment of whole blood comprises a dialyzable chemotherapeutic agent and a dialyzable fluorescable tracer means. The removal rate of the fluorescable tracer compound from treated blood during hemodialysis is a function of the removal rate of unreacted chemotherapeutic agent present. The residual chemotherapeutic agent concentration after hemodialysis is ascertained by measuring the concentration of the fluorescable tracer compound in a dialysate using fluorometric techniques.

A system for monitoring low molecular weight compounds in blood plasma in the body by optical means includes a chamber which can be inserted into the blood stream and which contains specific receptor sites for the plasma constituent to be analyzed. The chamber interior is isolated from the blood by a dialysis membrane which permits the plasma constituents to diffuse into the chamber. A competing ligand for the receptor sites is placed within the chamber, but due to its relatively large molecular size the competing ligand cannot escape through the dialysis membrane into the bloodstream. Light emitted or absorbed by the competing ligand gives a measure of the concentration of the selected low molecular weight compounds in the blood.