Abstract: Test apparatus for detecting an analyte (A) contained in a sample liquid, comprising a dry porous carrier (10), on which a selective binder (12), capable of selectively binding the analyte (A) after the carrier (10) is wetted with the sample fluid, is arranged in a reaction zone (20), wherein furthermore arranged in the reaction zone (20) are: a complex, formed by a biomarker (B) and the first complexed reporter partner of a pair of reporters, interacting to produce an optically detectable signal, of reporter enzyme (E) and reporter substrate (S), and the second, free reporter partner of the pair of reporters, wherein the biomarker (B), in terms of the selectivity of the binding capacity of the selective binder (12), is equivalent to the analyte (A) and competitive therewith and wherein binding of the selective binder (12) to the complexed biomarker (B) impedes the interaction between the complexed and the free reporter partners.