To the Editor: To establish sensitivity, specificity,
and likelihood ratios for a diagnostic test, the investigation must include
both patients with and without the disease. However, in their review of carpal
tunnel syndrome (CTS), Drs D'Arcy and McGee1
define likelihood ratios as the "odds that a given finding would occur in
a patient with CTS as opposed to one without CTS," but they excluded articles
with asymptomatic control groups. The use of asymptomatic control subjects
ensures that patients are included who do not have any evidence of nerve compression.
Thus, the 14 studies that D'Arcy and McGee excluded on this basis should have
been included in the assessment of the CTS diagnostic criteria.
Mackinnon SE, Novak CB, Landau WM. Clinical Diagnosis of Carpal Tunnel Syndrome. JAMA. 2000;284(15):1924-1925. doi:10-1001/pubs.JAMA-ISSN-0098-7484-284-15-jlt1018