Controlled dispersion flow analysis system

A flow analysis method for measuring, in a blood sample containing a plurality of lipoprotein classes, the distribution of cholesterol among said lipoprotein classes, comprising:

• a) separating the blood sample in a sample container into two or more fractions representing different lipoprotein classes to form a gradient;
• b) providing a continuous, non-segmented stream of reagent which continuously flows from a reagent source to a detector;
• c) introducing each sample fraction in said gradient into the reagent streams, comprising programming a controller to open a first inlet line connected to said sample container wherein said first line feeds the blood sample into the reagent stream in a continuous succession upstream from the detector;
• d) reacting each sample fraction with the reagent as the sample fractions flow from a reaction tube toward said detector to produce a measurable reaction signal indicative of the cholesterol concentration in each sample fraction of the gradient while controlling dispersion of the sample fractions within the reagent stream;
• e) detecting the end of the sample with a meniscus detector disposed in the first inlet line before introduction of the sample into said reagent stream;
• f) backflushing a said inlet line with a wash solution in response to detection of the end of the sample by said meniscus detector, comprising programming a said controller to open a second inlet line connected to source of said wash solution while said first inlet line remains open, and close said first inlet line containing said sample a predetermined time period after the second inlet line is open, wherein said second inlet line remains open to deliver said wash solution to said reaction tube.

An apparatus for measuring the cholesterol distribution among plasma lipoproteins in a blood sample separated into two or more gradients containing said plasma lipoproteins, said apparatus comprising:

• a) a reaction tube having an inlet and an outlet;
• b) a reagent supply connected to the inlet of said reaction tube for providing a continuous, non-segmented stream of reagent in said reaction tube;
• c) a fluid sampling circuit for alternately introducing a baseline fluid and said blood plasma sample into said reaction tube to be mixed with said continuous reagent stream, said fluid sampling circuit including:
• i) a first inlet line connected to a source of a baseline fluid,
• ii) a second inlet line connected to a sample container containing said blood plasma samples, and
• iii) an outlet line connected to said reaction tube for alternately feeding said baseline fluid and said blood plasma sample into said reaction tube;
• d) sensing means disposed along said second inlet line for detecting the end of said blood plasma sample;
• e) an electrical controller for selectively controlling the flow of said baseline fluid and said blood plasma sample, said controller programmed to:
• i) open said second inlet line to feed the blood plasma sample into said reaction tube,
• ii) open said first inlet line when the end of said sample is detected by said sensing means while said second inlet line remains open to back-flush said second inlet line with said baseline fluid, and
• iii) close said second inlet line a predetermined time period after said first inlet line is opened while said first inlet line remains open to deliver baseline fluid to said reaction tube;
• (f) a detector connected to the outlet of said reaction tube for measuring a characteristic of the fluid flowing through said detector indicative of the cholesterol concentration in said fluid;
• g) a fixture for simultaneously receiving and holding a plurality of sample containers, each of which contains a separate blood plasma sample;
• and
• h) means for automatically and sequentially feeding said blood plasma samples into said fluid sampling circuit, wherein said electrical controller is programmed to close said first inlet line and open said second inlet line to start the flow of said blood plasma sample through said fluid sampling circuit in response to detection of a sample container in said fixture.

A flow analysis method for measuring, in a blood sample containing a plurality of lipoprotein classes, the distribution of cholesterol among said lipoprotein classes, comprising:

• a) separating the blood sample in a sample container into two or more fractions representing different lipoprotein classes to form a gradient;
• b) receiving and holding the sample container in a fixture;
• c) providing a continuous, non-segmented stream of reagent which continuously flows from a reagent source to a detector;
• d) detecting the presence of the sample container In the fixture;
• e) upon detecting the presence of the sample container in the fixture, automatically and sequentially introducing each sample fraction in the gradient into a reagent stream, comprising programming a controller to open a first inlet line connected to said sample container wherein said first inlet line feed the blood sample into the reagent stream in a continuous succession upstream from the detector;
• f) reacting each sample fraction with the reagent as the sample fractions flow from a reaction tube toward the detector to produce a measurable reaction signal indicative of the cholesterol concentration in each sample fraction of the gradient while controlling dispersion of the sample fractions within the reagent stream;
• g) detecting the end of the sample with a meniscus detector disposed in the first inlet line before introduction of the sample into the reagent stream;
• h) backflushing said inlet line with a wash solution in response to detection of the end of the sample by said meniscus detector, comprising programming said controller to open a second inlet line connected to a source of said wash solution while said first inlet line remains open and close said first inlet line containing said sample a predetermined time period after the second inlet line is open, wherein said second inlet line remains open to deliver said wash solution to said reaction tube.