Principal elements of the NIDIAG digestive study and the respective standard operating procedures (SOPs) used.

<p>Principal elements of the NIDIAG digestive study and the respective standard operating procedures (SOPs) used.</p

Set of standard operating procedures (SOPs) used in the NIDIAG study on persistent digestive disorders.

<p>Set of standard operating procedures (SOPs) used in the NIDIAG study on persistent digestive disorders.</p

Diagnostic challenges encountered during the NIDIAG study on persistent digestive disorders and proposed solutions.

<p>Diagnostic challenges encountered during the NIDIAG study on persistent digestive disorders and proposed solutions.</p

Country-specific enrolment characteristics of patients and controls in the NIDIAG study on persistent digestive disorders.

<p>Country-specific enrolment characteristics of patients and controls in the NIDIAG study on persistent digestive disorders.</p

Laboratory diagnostic techniques used and internally compared in the NIDIAG study on persistent digestive disorders.

<p>Laboratory diagnostic techniques used and internally compared in the NIDIAG study on persistent digestive disorders.</p