Method for serologic agglutination and other immunoassays performed in a thin film fluid sample
A method and system for performing a serological agglutination assay in a liquid sample. The system provides a simple method for creating an in-situ sample/reagent admixture within a sample analysis chamber without the use of any precision fluid-handling components.
1. A method for performing a serologic agglutination assay for one or more target analyte antibodies in a liquid sample, said method comprising the steps of:
a) providing a thin planar chamber having opposed planar surfaces, at least one of which is transparent, which chamber has a height that is equal to or less than 20 μm;
b) placing an effective amount of detectable first particles in said planar chamber, said first particles containing on their surfaces an antigen against which the target analyte antibodies are directed;
c) placing control particles, similar in size and shape to said first particles, in said chamber, said control particles differing from said first particles in color, and said control particles being devoid of said antigens, and disposing a volume of sample within the thin planar chamber such that at least a portion of the sample contacts both opposed planar surfaces of the chamber;
d) allowing or causing said detectable first particles and said sample to admix with each other whereby said target analyte antibodies, when present, will cause agglutination of said detectable first particles;
e) electronically imaging or scanning said admixture to detect individual aggregates of particles by analysis of patterns of pixel intensity resulting from aggregation of detected particles; and
f) determining the presence or absence of significant particle agglutination by comparing signals of any aggregated first particles with signals of any aggregated control particles.
2. The method of claim 1 wherein the detection of presence of agglutination of particles is performed by measuring pixel areas of agglutinated first particles with pixel areas containing any agglutinated control particles.
3. The method of claim 1 wherein the detection of agglutination of particles is performed by determining the percentage of particles of any given type that are aggregated or clumped.
4. The method of claim 1 wherein there are more than one class of separately distinguishable detectable first particles, each class containing different antigens so that multiple assays may be simultaneously performed in the same sample chamber.
5. The method of claim 1 wherein said first particles and said control particles are differentially marked so as to be distinguishable one from the other.