Abstract: A measuring device, intended for measurements on whole blood, comprises a sample fluid chamber for containing a blood sample, ion-selective potentiometric electrodes for measurement of the concentrations of sodium and potassium ions, a reference potentiometric electrode, an optical sensor for measuring the concentration of glucose by means of a color reaction, a cuvette having a window permitting spectrophotometric measurement of the level of haemoglobin, a conditioning (calibration) fluid chamber in which the ion-selective electrodes and the reference electrode are exposed to a conditioning (calibration) fluid comprising known concentrations of sodium and potassium ions (thereby facilitating calibration of the response of the ion-selective electrodes), a rupturable pack containing the conditioning fluid and from which the fluid is released into the conditioning fluid chamber upon application of pressure to the pack, and a wall part which partly defines the sample fluid chamber and has weakened areas which ar

Abstract: Subtilisin or subtilisin-like enzymes are used in rinse solutions for apparatus analyzing protein-containing biological liquids, such as blood analysis apparatus, to obviate measuring errors ascribable to protein deposits. A preferred rinse solution contains subtilisin, a borate buffer, and germicides.

Abstract: In order to counteract coagulation of a blood sample which is collected from an animal or a human body (24) and introduced into a receptacle, such as a syringe chamber (14), an anticoagulant is added to the sample within the receptacle. The anticoagulant may be capable of binding cation species in the blood, which are subsequently to be measured. Such cation species comprise hydrogen ions, ammonium ions, alkaline metal ions such as potassium and sodium ions, and alkaline earth metal ions such as magnesium and calcium ions. In order to compensate for the proportions of selected cation species which are bound by the anticoagulant, an additive containing such cation species is added to the blood sample so as to obtain substantially the same concentration of the selected cation species in an unbound condition in the anticoagulant treated blood sample as in the untreated blood sample.

Abstract: Salt bridge liquid for use in potentiometric measurement of blood or a blood liquid.The salt bridge liquid contains Na.sup.+ -ions and HCOO.sup.- -ions in substantially equimolar amounts, preferably in a concentration larger than or equal to 1 M, in particular about 4 M.When this salt bridge liquid is used, the potentiometric measurement will give corresponding results when measuring a blood sample and the corresponding plasma sample because the suspension effect which is caused by the erythrocytes and which is seen when using other salt bridge liquids is substantially eliminated. Furthermore, different blood samples with the same ion concentration but with varying erythrocyte content will give corresponding measuring results.