RT Journal Article SR Electronic T1 Observer variation in the interpretation of Gram-stained urethral smears: implications for the diagnosis of non-specific urethritis. JF The British Journal of Venereal Diseases JO Br J Vener Dis FD BMJ Publishing Group Ltd SP 134 OP 136 DO 10.1136/sti.57.2.134 VO 57 IS 2 A1 J R Willcox A1 M W Adler A1 E M Belsey YR 1981 UL http://sti.bmj.com/content/57/2/134.abstract AB A study was carried out to determine whether the diagnosis of non-specific urethritis was affected by differences in the microscopical interpretation of urethral smears between individual observers (interobserver variation) and the same observer on separate occasions (intraobserver variation). A marked degree of both intraobserver and interobserver variation was found which--depending on the diagnostic criteria adopted--could affect both the diagnosis and treatment of many patients attending a clinic of genitourinary medicine.