Objective: To evaluate the role of the Schellong test (ST) in forms of orthostatic dysregulation in comparison with the tilt-table test (TT).
Methods: 67 young males (mean age 22 +/- 4 years) from the military service, representing two different cohorts, were examined by ST and TT, which served as gold standard. 32 of the 67 subjects were asymptomatic while 35 had sought medical advice because of orthostatic complaints. The subjects subsequently were classified into four categories according to the TT: normal TT, orthostatic hypotension (OH), postural orthostatic tachycardia syndrome (POTS), and neurocardiogenic syncope (NCS). Chi-square test was used to calculate the sensitivity and specificity of ST in detecting forms of orthostatic dysregulation (OH, POTS and NCS).
Results: In total, TT detected 23 recruits with POTS, 16 with NCS and 2 with OH. Out of the 32 asymptomatic subjects only one was diagnosed having POTS by TT and ST, the rest had a normal ST and TT. For detecting POTS, ST sensitivity was 61% and specificity was 100% compared with TT. For detecting NCS, ST sensitivity was 31% and specificity 100% compared with the reference test, the TT. The data concerning OH could not be analyzed because of the small number of cases.
Conclusions: In conclusion the results of our study indicate that ST can be used in first line in the diagnosis of patients with orthostatic symptoms by the medical practitioner. If the ST is normal, further examination by TT is indispensable, because sensitivity of ST concerning POTS and NCS is relatively low.