The sera will be selected from the database of the Tropica biobank, based on the given exclusion/inclusion criteria.

The samples will be tested after thawing shortly before the procedures. Each serum sample will be used for running the two RDTs (IgG and IgG4). Two independent readers will report the test results blinded from each other. In case of discrepancies, a third reader will be involved.

Sera will be thawed at room temperature; 15 µL of serum will be added to the sample pad of each dipstick, which will then be placed upright into a well containing 3 drops of buffer. The pads at the bottom of the dipstick shall then wick up the buffer to run up the nitrocellulose membrane towards the absorbent pad. The results can be read after 15-20 minutes. The presence of the control line will indicate proper execution of the test, with valid result. In case of absence of this line, the result will be considered invalid. Positive results will be defined as test with presence of both control and positive (including faint) lines; negative results will be defined as tests with presence of control line only.

RDTs (IgG) results will be classified as positive or negative according to the manufacturer instructions. For the composite reference standard definition: a true positive will be defined as at least one positive faecal test result. True negative will be defined as all test results (faecal and serological) being negative.

RDTs (IgG4) results will be classified as positive or negative according to the manufacturer instructions. For the composite reference standard definition: a true positive will be defined as at least one positive faecal test result. True negative will be defined as all test results (faecal and serological) being negative.

Agreement between two independent readers of the RDTs results