Comparison of the performance of carcinogenic HPV typing of the Roche Linear Array and Qiagen LiquiChip® HPV assays.

BACKGROUND: Cervical cancer is caused by high-risk types of human papillomavirus (HPV). DNA testing of such high-risk types of HPV could improve cervical screening.The aim of the study was to compare the sensitivities and positive predictive values of two commercially available typing assays (Qiagen LQ and Roche LA) and to comparatively assess the distribution of HPV types with these two assays. METHODS: The study population comprised 311 ASCUS + women with abnormal pap tests who were HCII positive and who were admitted to three European referral gynecology clinics between 2007 and 2010 (Madrid, Marseille and Milan). All patients underwent LQ and LA tests. RESULTS: The sensitivity of the two assays for HPV typing was 94% for LQ and 99% for LA (compared with HCII). The overall concordance between LQ and LA was 93%. The three prevalent genotypes, HPV16, HPV18, and HPV31, were identified with a high concordance using the two assays: kappa 0.93, 0.83, and 0.91, respectively. Mixed genotypes were more frequently detected by LA than by LQ: 52% vs. 18%, respectively (p < .0001). CONCLUSIONS: These assays have a good clinical sensitivity for detecting HPV types in CIN2+ patients and allow the virus type to be detected in the same experiment. Our study revealed no significant difference between LQ and LA for CIN2+ or CIN3+ diagnosis, indicating similar distributions of HPV types and a mixed genotype detection that is higher for LA than for LQ.

Dried blood spot sampling for hepatitis B virus serology and molecular testing.

BACKGROUND AIMS: Dried blood spots (DBS) on filter paper have been successfully used to diagnose and monitor several infectious diseases. The aim was to investigate the performance of DBS in hepatitis B virus (HBV) diagnosis using commercial tests in comparison to standard methods. METHODS: Paired DBS and plasma samples were collected from 200 patients: 100 patients with HBsAg negative status and 100 patients with HBsAg positive status. In the latter patient, HBeAg reactivity was tested. Ten samples of anti-HBs were collected from people vaccinated against HBV. We also studied 50 patients with positive HBV DNA viral load in plasma and 10 HBV DNA negative patients. HBV genotypes and gene polymerase mutations were determined in 10 randomly selected HBV-infected patients. The DBS sample consisted of 50 µL of whole blood, i.e. a 12-mm paper card. RESULTS: The sensitivity thresholds of HBsAg and anti-HBs antibody were 0.30 ± 0.08 IU/mL and 18.11 ± 6.05 IU/mL, respectively, for DBS with 98% sensitivity and 100% specificity. Sensitivity was 98% and specificity 100% for the detection of HBV DNA on a blotter, considering an HBV DNA threshold of 914.1 ± 157.8 IU/ml. Ten patients had an HBeAg positive status in plasma, all were detected positive using DBS. HBV genotyping and mutation detection were successfully performed on DBS, with full concordance between the 10 paired DBS and plasma samples. CONCLUSION: This study shows DBS is a reliable alternative to plasma specimens for quantifying and detecting HBsAg, anti-HBs, HBeAg and genotyping. DBS may increase the opportunities for HBV testing and treatment follow-up in hard-to-reach individuals.

HPV genotype distribution according to severity of cervical neoplasia using the Digene HPV genotyping LQ test.

A new genotyping-based DNA assay (Digene LQ(®)) was developed recently. The primary aim was to assess the distribution of HPV types using this new assay in atypical squamous cells of undeterminate significance (ASCUS). The secondary aim was to correlate the HPV types with the severity of the disease. The study population comprised 376 ASCUS women. The women were all Hybrid Capture II (HCII) positive and were admitted in three European referral gynecology clinics between 2007 and 2010. A colposcopy with histological examination was performed in all these patients. HPV 16 was typed in 40 % of patients, HPV 18 in 7 %, and HPV 31 in 17 %, and 18 % of patients had mixed genotypes. Patients aged over 30 more often had the HPV 16 genotype than patients aged under 30 (29 % vs. 11 %, chi-square test p < 0.001). The risk of cervical intra-epithelial neoplasia of grade 2 or more (CIN2 +) when HPV 18 positive is lower than the probability associated with HPV 16 or HPV 31: 28 % vs. 58 % and 52 %, respectively (chi-square test, p = 0.005 and p = 0.05, respectively). The Digene LQ(®), a new sequence-specific hybrid capture sample preparation, is fast and efficient and allows high-throughput genotyping of 18 HR HPV types by PCR compared to traditional non-sequence-specific sample preparation methods.