A systematic nomenclature for quantities of the haemostatic system

The complex interplay of coagulation factors, fibrinolytic factors, and inhibitors characterizing the haemostatic system causes difficulties for devising useful measures of its status in a patient as well as for their calibration, comparability, and nomenclature. The latter problem is addressed by constructing examples of systematic generic quantity names based on IUPAC and IFCC recommendations having the general format "System-Component; kind of quantity" and considering the possibilities for each of these three items with both single and multiple components. The kinds of quantity comprise mass concentration, (amount-of-) substance concentration, catalytic (activity) concentration, time, relative arbitrary (amount-of-) substance concentration, relative time, and reciprocal relative time. For the coagulation system, the relative time specified by the use of thromboplastin reference material WHO 67/40 and the characterization of other thromboplastins by comparison with that reference material is discussed. A descriptive systematic name for international sensitivity index (ISI) is orthogonal regression slope (ORS). The recalculated value for the relative time of coagulation of a sample using any thromboplastin and its ORS is currently called international normalized ratio (INR), but is simply a relative time with the ORS specified.