Abstract: A method and apparatus for handling samples such as blood samples for hemostasis. The sample is transferred from a test tube into a cuvette which has been released from a supply of cuvettes. Prior to transferring the sample, a needle is introduced into the sample and automatically senses the level or height of the sample in the test tube. The presence of vials of reagent is optically confirmed. Reagents are to be delivered through a delivery tube into the cuvette and the delivery tubes are initially primed with reagent. The presence and orientation of the cuvette are verified and the sample transferred into the cuvette, the reagent automatically delivered into the cuvette, and the reaction such as, but not limited to, blot clotting occurs in the cuvette. The occurrence of the reaction is optically confirmed. The system and method controls the sequential release of stacked cuvettes in addition to confirming the presence and proper orientation of the cuvettes.

Abstract: A computer controlled diagnostic densitometer for analyzing optical density patterns of blood samples or the like scans a sample and generates an analog waveform signal representative of the scanned optical density pattern. The analog signal is amplified, digitized, stored in a memory and is later read from memory to reconstruct a visual display of the waveform for analysis. Several types of optical density pattens may be scanned which result in analog signals of different amplitudes and signal-to-background noise ratios. An improved amplification system automatically preadjusts the gain and reference value of the analog signal prior to digitization in order to substantially eliminate background noise in the signal and produce substantially full scale analog signal values. The gain and reference value preadjustments are performed by a pair of corresponding multipliers which multiply the analog signal by memory-stored digital data which is unique to the type of optical density pattern being scanned.

Abstract: A method of optically scanning a plurality of optical density patterns, such as blood samples or the like is provided wherein the samples are arranged in rows and each include a plurality of optical density segments extending along a first axis, and wherein the segments generally form columns of like segments along a second axis. The optical densities of a row of segments are first scanned along the first axis, following which the centerlines of each segment in the scanned row is determined along the first axis. Then, the segments of each column are scanned along the corresponding, previously determined centerline. The centerline of each segment is determined by displacing a scanning head relative to the sample along the first axis, measuring the optical density of each segment and correlating the magnitude of the measured optical density with the relative displacement between the head and the samples.