Effect of the Standardization of Diagnostic Tests on the Prevalence of Diabetes Mellitus and Impaired Fasting Glucose

BACKGROUND: Without standardization of medical laboratory's testing practices, there is an increase in false diagnoses when relying on test results. However, the effect of test standardization is difficult to assess numerically. This study's purpose is to quantify the effect of the standardization level of a laboratory on the prevalence of diabetes mellitus (DM) and impaired fasting glucose (IFG). METHODS: Laboratories were classified into three levels: ‘highly-standardized laboratory,’‘basically-standardized laboratory,’ and ‘non-standardized laboratory.’ Based on the results of Korean External Quality Assessment Scheme (KEQAS), the cutoff values for diagnosis of DM and IFG were recalculated, given false positive and false negative rates. RESULTS: The prevalence of DM and IFG in the population as a whole was estimated using the 2013 Korea National Health and Nutrition Examination Survey (KNHANES) database. When the prevalence of DM from KNHANES was 11.88% (95% confidence interval [CI], 10.59%–13.17%), the proportion with a systematic false error ranged from 10.91% (95% CI, 9.65%–12.17%) to 13.09% (95% CI, 11.74%–14.45%). The prevalence of IFG varied from 13.59% (95% CI, 12.25%–14.91%) to 40.49% (95% CI, 38.54%–42.43%), in contrast to 24.58% (95% CI, 22.85%–26.31%) of the reference value. The prevalence of DM and IFG tended to be over- and under-estimated more as the laboratory standardization level became lower, respectively. CONCLUSION: Our study proved that standardization of clinical laboratory tests is an important factor affecting the prevalence estimation of national disease statistics based on the simulation using KNHANES data.

The comparison of Conventional Pap smears with Liquid Pap smears (PrepStain(TM) System) in Cervical Pap smears / 대한산부인과학회지

OBJECTIVE: To Compare the conventional Pap smear with the Liquid Pap smear in screening of cervical cancer and to evaluate the correspondence of their biopsy results. METHODS: From August 1, 2003 to July 31, 2005, the conventional Pap smears and the Liquid Pap smears were performed in 12,757 and 6,870 women, respectively. The results of 252 conventional Pap smear and 227 Liquid Pap smear were confirmed by colposcopic biopsy and evaluated for sensitivity, specificity, positive predictability, negative predictability and false negativity. RESULTS: In Liquid Pap smear, there were higher proportions of ASCUS, LSIL, HSIL and CIS. And the ratio of ASCUS/LSIL were 3.32 and 3.04 in conventional Pap smear and Liquid Pap smear respectively. The conventional Pap smear showed sensitivity 71.8%, specificity 93.9%, positive predictability 82.3%, negative predictability 89.4%, and false negativity 28.2%, while the Liquid Pap smear showed higher sensitivity (72.6%), specificity (96.1%), and positive predictability (89.8%), and lower negative predictability (88.0%), and false negativity (27.4%). The positive predictability was significantly higher (95% C.I.: 1.3-13.7). CONCLUSION: The positive predictability was significantly improved in the Liquid Pap smear. Therefore, the Liquid Pap smear is a more useful method in screening of cervical cancer.

Comparison of Efficacy between MonoPrep(R) and Papanicolaou Smear for Cervical Cancer Screening / 대한산부인과학회잡지

OBJECTIVE: To compare the specimen adequacy and cytologic diagnostic results of MonoPrep(R), a type of liquid based preparation, with the conventional Pap smear. METHODS: In randomly selected 156 patients who visited the department of Obstetrics and Gynecology, Ajou University Hospital for cervical biopsy, conventional Pap smear and matched MonoPrep(R) were performed. Statistical analysis was performed with chi-square test. RESULTS: There were more "Unsatisfactory" and "Satisfactory but limited by (SBLB)" results in the conventional Pap smear group, even though no statistical significance could be found between the two groups. ASC/LSIL ratio was significantly decreased in the MonoPrep(R) group, showing 0.4 with MonoPrep(R) and 1.9 with conventional Pap smear demonstrating a 78.4% decrease (P<0.001). In detecting abnormal cervical lesions, conventional pap smear showed a sensitivity of 87.7%, positive predictability of 82.3%, false negativity of 10.3%, while MonoPrep(R) showed a sensitivity of 94.8% (P=0.04), positive predictability of 97.4% (P<0.001), and false negativity of 2.6% (P=0.016). CONCLUSION: MonoPrep(R) is more effective for the detection of cervical lesions with higher sensitivity and lower false negativity compared to conventional pap smear.