Which are more correctly diagnosed: Conventional Papanicolaou smears or Thinprep samples? A comparative study of 9 years of external quality-assurance testing

Abstract

BACKGROUND The Royal College of Pathologists of Australasia Cytopathology Quality Assurance Program offers external testing in gynecologic cytology to Australasian and international laboratories. Laboratory interpretation of conventional Papanicolaou (Pap) smears is compared with interpretation of liquid-based cervical cytologic (ThinPrep) samples. METHODS Conventional Pap smears and ThinPrep samples were distributed to participating laboratories annually over 9 years (from 2004 to 2012), and a range of entities was tested. Target responses and major error rates and diagnostic trends over time were explored. RESULTS In total, 23,373 conventional Pap smears and 14,104 ThinPrep samples were reported. Both Australasian (P =.003) and international (P