Patent ID: 6743398
Filing Date: 2004-06-01
Classification: G01N

Abstract:
A serum/clot separation surface determination apparatus comprising:a test tube containing a blood sample which is separated into a serum and a clot by a silicon separating medium having a permeability smaller than that of the serum/clot; a test tube holder which holds the test tube; a detection coil fitted on an outer surface of the test tube held by the test tube holder; a measurement signal supply unit which supplies a measurement signal having a given frequency to the detection coil; position control means which starts operation in response to a control signal for variably controlling a relative position between the detection coil and the test tube in a longitudinal direction of the test tube by moving at least one of the detection coil and the test tube and for performing a return operation to return the detection coil and the test tube to an initial position in response to a return operation signal; signal level detection means which detects a level of the measurement signal that varies with the relative position controlled by the position control means; and determination means which determines a position of a sample separation surface obtained by the silicon separating medium based on the level of the measurement signal detected by the signal level detection means, wherein the determination means comprises means for differentiating a rising of the measurement signal corresponding to a surface of the separating medium to form a differential signal, means for outputting a serum separation surface judgment signal when a level of the differential signal exceeds a level of a reference signal, and means for providing the judgment signal to the position control means as the return operation signal, when the detection coil moves upward and the test tube moves downward relative to each other.