Unexplained complaints (UCs) can be defined as complaints that, after a proper history taking and physical examination, do not seem to be explained by either somatic or psychiatric diseases, nor by the patient's psychosocial context [ [1] Dinant G.J. van Wijk M.A.M. Janssens H.J.E.M. Somford R.G. de Jager C.J. Beusmans G.H.M.I. et al. NHG-standaard bloedonderzoek. Algemene principes en uitvoering in eigen beheer. Huisarts Wet. 1994; 37: 202-211 Google Scholar ]. Among the UCs most frequently seen in primary care are fatigue, abdominal complaints, dizziness, musculoskeletal complaints, and headache [ 2 van der Weijden T. van Velsen M. Dinant G.J. van Hasselt C.M. Grol R.P.T.M. Unexplained complaints in general practice. Prevalence, patients' expectations, and professionals' test-ordering behavior. Med Decis Making. 2003; 23: 226-231 Crossref PubMed Scopus (78) Google Scholar , 3 Sheehan J.D. The management of medically unexplained symptoms. Semin Gastrointest Dis. 1999; 10: 30-36 PubMed Google Scholar ]. Thus, UCs reflect a broad range of clinical pictures. In the literature, these complaints are frequently referred to as medically unexplained symptoms, although some authors use this term for somatoform disorders as well [ [4] Burton C. Beyond somatisation: a review of the understanding and treatment of medically unexplained physical symptoms (MUPS). Br J Gen Pract. 2003; 53: 231-241 PubMed Google Scholar ]. Therefore, we prefer the term “unexplained complaints.” Furthermore, UCs will often be self-limiting, but may also be the first sign of serious disease. These diagnostic uncertainties make physicians feel uneasy when dealing with patients presenting with UCs. This may result in unnecessary reconsulting, superfluous laboratory and other testing, or a prolonged period of waiting and seeing [ [5] Knottnerus J.A. Knipschild P.G. van Wersch J.W.J. Sijstermanns A.H.J. Unexplained fatigue and hemoglobin: a primary care study. Can Fam Physician. 1986; 32: 1601-1604 PubMed Google Scholar ]. In addition, the burden of disease in terms of both quality of life and costs may be high, especially when complaints become chronic [ [6] Katon W.J. Walker E.A. Medically unexplained symptoms in primary care. J Clin Psychiatry. 1998; 59: 2015-2021 Google Scholar ].