Abstract: Methods for quantitatively measuring the amount of an analyte of interest in a fluid sample are disclosed. The methods involve providing a membrane having an application point, a detection zone, and a contact region, where the contact region is between the application point and the detection zone, and has test particles and internal control particles imbedded within it; contacting the application point with the fluid sample; maintaining the membrane under conditions sufficient to allow fluid to transport analyte by capillary action to the contact region, where the analyte binds to the test particles; further maintaining the membrane under conditions sufficient to allow fluid to transport analyte-bound test particles and internal control particles to the detection zone, where they interact with a detection reagent; and detecting the amount of test particles and the amount of internal control particles in the detection zone.

Abstract: Methods for measuring the amount of an analyte in a membrane, by applying to the membrane a clearing agent, are disclosed. The clearing agent can be an agent that has approximately the same refractive index as the membrane; alternatively, the clearing agent can be a dissolving agent, that dissolves the membrane. The analyte can be labelled to facilitate detection. Representative labels include fluorescent labels and detectable particles.

Abstract: Methods of calculating the platelet count of an individual, by measuring the amount of a released platelet granule protein of interest in a sample of whole blood or of platelet-rich plasma from the individual, are described. The platelet granule protein of interest is either thrombospondin or .beta.-thromboglobulin. The amount of released platelet granule protein of interest in the whole blood sample or platelet-rich plasma sample is measured using an enzyme-linked immunosorbent assay; radioimmunoassay; sandwich assay; a quantitative immunochromatographic assay; or non-solid phase nephelometry. The platelet count is directly related to the amount of released platelet granule protein of interest in the sample, and can be determined from the amount of platelet granule protein of interest that is released from a known number of platelets.

Abstract: Quantitative immunochromatographic assays for measuring the amount of an analyte, and an apparatus for use in the assays, are disclosed. The assays involve obtaining a fluid sample which contains the analyte; supplying a RAMP.TM. apparatus which includes a membrane having an application point, a detection zone, and a contact region, where the contact region is between the application point and the detection zone, and has antibody-coated particles imbedded within it; contacting the application point with the fluid sample; maintaining the RAMP.TM.