Disposable extracorporeal conduit for blood constituent monitoring

(57) Cuvette (19) which the blood style which carries out summary pulsation passes. Cuvette (10) has two opposite walls mutually estranged at intervals of the predetermined division which changes along with pulsation of a blood style. Change of a predetermined division interval declines by the sealed air pocket. A lead pipe consists of materials which make the wavelength of a selected electromagnetic radiation light penetrate. Radiation is performed by the photoelectron radiator (122) and synchrotron orbital radiation and the synchrotron orbital radiation after cuvette passage are detected in a 光電 detector (104). The detected radiant quantities are calculated with an arithmetic unit (150), and spectrophotometry technology is used for an arithmetic unit asking for constituent-of-blood concentration. It is desirable to use the both sides of cuvette (10) and spectrophotometry technology for asking for hematocrit value change of the blood of the patient who undergoes dialysis into hemodialysis, and to decrease the amount change of blood of the patient under dialysis.