Patent ID: 7569397

Claim:
A method for testing a sample for the presence of a ligand, comprising: a) obtaining a test device having a housing, a strip of sorbent material, and a filter, the housing defining a first opening having a top wall defining a second opening and a bottom wall having a window, the strip of sorbent material including a test site having an immobilized ligand-binding mechanism, said test site located directly below said second opening and adjacent said window, the strip of sorbent material being disposed within said housing and defining a horizontal flow path from adjacent said first opening to said test site, the filter for filtering the sample, the filter located in or adjacently below the second opening and directly above the test site; b) applying the sample to the filter; c) after said applying, applying a solution through said first opening to said sorbent material; and d) inspecting said test site through said window to determine an indication of the presence or lack thereof of the ligand in the sample.