Immunoassay test device with two fluid flow paths for detection and differentiation of two or more analytes

A method for diagnosing an infection in a subject, comprising:

• depositing a fluid sample from the subject on a sample receiving zone configured to receive a fluid sample, wherein the sample receiving zone is the sole sample receiving zone provided on a device comprising a plurality of fluid flow paths;
• distributing the fluid sample along a first fluid flow path and a second fluid flow path;
• wherein a first portion of the fluid sample is distributed via the first fluid flow path to a first label zone comprising a first mobilizable, detectable species that binds IgM antibodies present in the fluid sample, and subsequently to a first test line positioned downstream of the first label zone, wherein the first test line comprises a first immobilized species capable of specifically binding a conjugate comprising the first mobilizable, detectable species and one or more IgM antibodies from the fluid sample;
• wherein a second portion of the fluid sample is distributed via the second fluid flow path to a second label zone comprising a second mobilizable, detectable species that binds IgG antibodies present in the fluid sample, and subsequently to a second test line positioned downstream of the second label zone, wherein the second test line comprises a second immobilized species capable of specifically binding a conjugate comprising the second mobilizable, detectable species and one or more IgG antibodies from the fluid sample;
• wherein only one of the first and second fluid flow paths comprises a reference line comprising an immobilized species having binding affinity for a detectable moiety provided upstream of the reference line;
• and
• inspecting the first and second test lines for the presence or absence of the mobilizable, detectable species.