A biosensor has an underfill detection system that determines whether a sample of a biological fluid is large enough for an analysis of one or more analytes. The underfill detection system applies an excitation signal to the sample, which generates an output signal in response to the excitation signal. The underfill detection system switches the amplitude of the excitation signal. The transition of the excitation signal to a different amplitude changes the output signal when the sample is not large enough for an accurate and/or precise analysis. The underfill detection system measures and compares the output signal with one or more underfill thresholds to determine whether an underfill condition exists.

A biological reaction apparatus for receiving at least one substrate having a sample located in a sample region, and a separate cover, such that a reaction chamber is formed between the cover and substrate over the sample region, wherein the apparatus includes a locating means to locate the substrate; a cover locating means for locating and moving the cover with respect to the substrate; a fluid dispensing means for dispensing fluid into the reaction chamber; and a draining mechanism; wherein the draining mechanism includes wicking means.

A method of distinguishing a control solution from a sample in an electrochemical test sensor is performed. The method includes adding a control marker to the control solution. The control solution includes the control marker and analyte. The test sensor includes working and counter electrodes, and a reagent. A potential is applied to the test sensor to oxidize the control marker and the analyte. The resulting electrical current is measured. A potential is applied to the test sensor lower than the other potential in which the potential is sufficient to oxidize the analyte and not the control marker. The resulting electrical current is measured. Determining whether a control solution or a sample is present based on the measured electrical currents. To increase the measured current, a salt may be added to the control solution in an amount sufficient to increase the electrical current by at least 5% as compared to a control solution in the absence of a salt.

The instant invention provides an economical flow-through method for determining amount of target proteins in a sample. An antibody preparation (whether polyclonal or monoclonal, or any equivalent specific binding agent) is used to capture and thus enrich a specific monitor peptide (a specific peptide fragment of a protein to be quantitated in a proteolytic digest of a complex protein sample) and an internal standard peptide (the same chemical structure but including stable isotope labels). Upon elution into a suitable mass spectrometer, the natural (sample derived) and internal standard (isotope labeled) peptides are quantitated, and their measured abundance ratio used to calculate the abundance of the monitor peptide, and its parent protein, in the initial sample.

A method for performing an assay on a liquid sample for the detection of one or more analytes of interest in an assay device having a flow path which includes a sample zone and detection zone thereon includes: dispensing the sample onto the sample zone; combining the sample and a reagent, wherein the sample and reagent may be combined prior to addition of the sample to the sample zone or on the assay device, flowing the combined sample/reagent by capillary action into and through the detection zone having capture elements bound thereto, wherein a signal at least partially representative of the presence or concentration of analyte(s) is produced and detected; determining a reaction time or reaction volume; and determining the concentration of the analyte by using both the detected signal and the reaction time or reaction volume.

Provided are methods of detecting the presence or amount of a dihydroxyvitamin D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a dihydroxyvitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. In certain preferred embodiments the methods include immunopurifying the dihydroxyvitamin D metabolites prior to mass spectrometry. Also provided are methods to detect the presence or amount of two or more dihydroxyvitamin D metabolites in a single assay.

The formulations, systems, and methods disclosed herein permit automated preparation of specimens (e.g., biological specimens) for examination. The disclosed formulations, systems, and methods provide fast, efficient, and highly uniform specimen processing using minimal quantities of fluids. The methods include at least a fixing phase for fixing a specimen to a substrate such as a microscope slide, a staining phase for staining the specimen, and a rinsing phase for rinsing the specimen. One or more of the fixing, staining, and rinsing phases include one or more agitation phases for distributing reagents evenly and uniformly across the specimen. The systems can be implemented as a standalone device or as a component in a larger system for preparing and examining specimens.

The present invention relates to a method of preparing analyses of total blood samples and to a device that is useful for implementing the method, said samples being conserved in tubes including at least one identification means for identifying the sample, the device comprising: at least one compartment constituting a said storage zone for storing said tubes before and after analysis; and at least one said read means for reading said identification means of said tubes; and at least one preparation zone for preparing said blood samples prior to analysis and including means for verifying and/or treating said tubes containing said samples, and in particular at least one agitator means for agitating said tubes; and at least one access zone giving access to at least one automatic analyzer of total blood, said access zone enabling a said tube to be placed in said analyzer; and robotic gripper and displacement means controlled by an automatic controller and suitable for taking hold of and replacing said tubes individually in said storage zone and for conveying them in at least three directions XYZ between said storage zone, said preparation zone and said access zone giving access to said analyzer, said analyzer preferably being connected to and/or controlled by said automatic controller.

A parallel processing system for processing samples is described. In one embodiment, the parallel processing system includes an instrument interface parallel controller to control a tray motor driving system, a close-loop heater control and detection system, a magnetic particle transfer system, a reagent release system, a reagent pre-mix pumping system and a wash buffer pumping system.

A biosensor has an underfill detection system that determines whether a sample of a biological fluid is large enough for an analysis of one or more analytes. The underfill detection system applies an excitation signal to the sample, which generates an output signal in response to the excitation signal. The underfill detection system switches the amplitude of the excitation signal. The transition of the excitation signal to a different amplitude changes the output signal when the sample is not large enough for an accurate and/or precise analysis. The underfill detection system measures and compares the output signal with one or more underfill thresholds to determine whether an underfill condition exists.