http://www.cdc.gov/h1n1flu/guidance/rapid_testing.htm

This interim guidance provides an overview of the sensitivities of rapid influenza diagnostic tests (RIDT) in detecting novel influenza A (H1N1) virus in order to help guide the reporting and interpretation of test results. This document does not discuss either direct (DFA) or indirect immunofluorescence assays (IFA). This guidance is primarily intended for clinical laboratories and clinical practices conducting influenza testing on respiratory specimens from patients with suspected novel influenza A (H1N1) virus infection.