Significance of “Not Detected but Amplified” Results by Real-Time PCR Method for HPV DNA Detection

Human papillomavirus (HPV) infection is an important etiologic factor in cervical carcinogenesis. Various HPV DNA detection methods have been evaluated for clinicopathological level. For the specimens with normal cytological finding, discrepancies among the detection methods were frequently found and adequate interpretation can be difficult. 6,322 clinical specimens were submitted and evaluated for real-time PCR and Hybrid Capture 2 (HC2). 573 positive or “Not Detected but Amplified” (NDBA) specimens by real-time PCR were additionally tested using genetic analyzer. For the reliability of real-time PCR, 325 retests were performed. Optimal cut-off cycle threshold (CT) value was evaluated also. 78.7% of submitted specimens showed normal or nonspecific cytological finding. The distributions of HPV types by real-time PCR were not different between positive and NDBA cases. For positive cases by fragment analysis, concordance rates with real-time PCR and HC2 were 94.2% and 84.2%. In NDBA cases, fragment analysis and real-time PCR showed identical results in 77.0% and HC2 revealed 27.6% of concordance with fragment analysis. Optimal cut-off CT value was different for HPV types. NDBA results in real-time PCR should be regarded as equivocal, not negative. The adjustment of cut-off CT value for HPV types will be helpful for the appropriate result interpretation.

Cytological findings in scintigraphically nonfunctioning thyroid nodules

Background/Aim. The major one among the procedures for evaluating changes in the thyroid nodules is fine needle aspiration biopsy (FNAB). Thyroid scintigraphy is commonly used in diagnostic algoritham of nodules. Less than 5% of examined nodules show to be malignant. Scintigraphically, nodules could be classified as functional and nonfunctional. It is estimated that the risk of malignacy in nonfunctional nodules ranges from 8% to 25% and more. Aspiration punction provides 100% specific and positive predictive value. The aim of the study was to establish the distribution of cytological findings in nonfunctioning thyroid nodules. Methods. The prospective study enrolled 112 patients, 104 women and 8 men, submitted to thyroid scintigraphy for known thyroid nodule disorder. Scintigraphy was performed about half an hour after iv administration of 74 MBq of sodium-pertehnetate. A pin hole collimator was used. Scintigrams were visually evaluated, and absence of radiopharmaceutic in a nodule was estimated as nonfunctional one. Such nodules were afterwards subjected to FNAB and material obtained was cytologically analyzed. Results. In our patients nonfunctioning nodules comprised tissue of colloid struma, thyroid cyst, regular thyroid tissue, follicular lesion, oxiphillic lesion, papillary carcinoma tissue and tissue of lymphocytic thyroiditis. The most frequent cytological finding were colloid cysts (52%). A total of 70% were female nodules. Five citological findings were histopathologically analyzed. Conclusion. Cytological finding of nonfunctional nodules determines of the decision on radical therapy, and our preliminary results imply the need of FNAB routine use in nuclear medicine practice.