Method for measuring specific binding assays

A method for reading an assay cartridge having a known width with an interrogating light beam in an automated patient sample analysis instrument having a rotating carriage for receiving and centrifuging a plurality of self-contained, elongated assay cartridges, wherein each cartridge has a plurality of axially positioned immiscible chemical layers for performing a predetermined assay, comprising the following steps:

• a) uniquely identifying and determining the position of each cartridge and defining a measurement window for each cartridge;
• b) dividing the width of each measurement window into (n) number of equally spaced measurement intervals;
• c) rotating the carriage at least (n) times;
• d) on each successive rotation, identifying a subject measurement interval and illuminating the cartridges with light from a light source and measuring the intensity of light emanating from the subject measurement interval of each cartridge so that after the carriage is rotated (n) times, (n) number of measurements, one for each of said (n) measurement intervals, are taken for each cartridge;
• e) recording each of the (n) measurements for each cartridge;
• f) repeating steps c), d) and e) (x) number of times;
• g) summing the (x) number of repeated measurements for each measurement interval and for each cartridge and recording the summed resultant measurements;
• and
• h) selecting a number (y) of the largest averaged resultant measurements for each cartridge as indicative of a maximum measurement for each cartridge, whereby a reliable reading of the assay cartridge with the interrogating light beam is obtained.

A method for automatically performing analysis of patient sample with self-contained, elongated assay cartridges, wherein each cartridge has a preprinted assay code thereon and defines a cartridge axis and a reaction fluid contained in an internal receptacle sealed with a releasable seal, comprising the steps of:

• providing an automated patient sample analysis instrument having a rotatable carriage for receiving and centrifuging a plurality of the assay cartridges in a spaced apart fashion, light emitters and a light detector for performing transverse absorption and axial fluorescence measurements, an optical reader for reading a preprinted assay code on tile cartridges, a heater for controlling the temperature of the cartridges, and a controller having a memory for controlling the instrument, for storing measurements and predetermined assay procedures, and for performing calculations;
• introducing patient sample into at least one cartridge and placing the cartridge into the carriage;
• rotating the carriage at a first speed;
• identifying the position of the cartridge in the carnage and reading the assay code thereon;
• loading a matching assay procedure from the memory to the controller;
• rotating the carriage at a second speed higher than the first speed to centrifuge the cartridge;
• opening the releasable seal to cause the reaction fluid to be mixed with the patient sample;
• reducing the carriage to a speed slower than the second speed;
• incubating and agitating the cartridges;
• increasing rotation of the carriage speed to the second speed;
• reading measurements from the cartridges according to the predetermined assay procedures by
• a) dividing the width of each cartridge into (n) number of equally spaced measurement intervals;
• b) rotating the carriage;
• c) on each successive rotation, illuminating the cartridges with light from a light source and measuring the intensity of light emanating from each cartridge so that after the carriage has been rotated (n) times, (n) number of measurements, one for each of said (n) measurement intervals, are taken for each cartridge;
• d) recording each of the (n) measurements for each cartridge;
• e) repeating steps b), c) and d) (x) number of times;
• f) averaging or summing the (x) number of repeated measurements for each measurement interval and for each cartridge and recording the averaged or summed resultant measurements;
• and
• g) selecting a number (y) of the largest averaged or summed resultant measurements for each cartridge as indicative of a maximum measurement for each cartridge, whereby a reliable reading of optical properties of rotating cartridges is obtained.