A small-scale external quality assessment for PCR detection of group B streptococcus in China.

BACKGROUND: Group B streptococcus (GBS) is considered a leading cause of maternal and infant morbidity and mortality. Molecular diagnosis is a routinely used approach for GBS screening to protect pregnant women and prevent early-onset GBS neonatal disease. The objective of this study was to identify issues and guarantee the dependability of GBS molecular diagnosis by an external quality assessment (EQA) scheme. METHODS: The EQA panel comprised eight samples spiked with 10-fold dilutions of GBS suspension (20-2,000,000 copies/mL), and 2 negative control samples. The panels were coded randomly and distributed to participating laboratories for GBS detection. RESULTS: In total, 44 participating laboratories submitted results with eight commercial GBS PCR assays and one in-house assay. Among them, 36 obtained an acceptable or higher performance score, while 8 required improvement. Among the 440 results returned, 62 (14.1 %) were incorrect, including 5 false positives and 57 false negatives. CONCLUSIONS: Our small-scale EQA showed that most participating laboratories have reliable diagnostic capacities for GBS PCR detection. Nonetheless, further improvements in the detection performance of some laboratories are required, particularly with low-concentration samples. Our survey also reinforces the use of EQA as an essential tool to evaluate the overall proficiency of clinical laboratories.

External quality assessment for the molecular detection of microsatellite instability in China, 2021-2022.

BACKGROUND: Microsatellite instability (MSI) analysis of tumors informs Lynch syndrome testing, therapeutic choice, and prognosis. The status of MSI is mainly detected by polymerase chain reaction coupled with capillary electrophoresis. However, there are various assays with different detection loci and the obtained results may vary. The objective of this study was to evaluate the concordance among different assays and the performance among different laboratories. METHODS: External quality assessment (EQA) for the detection of MSI was performed in 2021 and 2022. Each sample panel consisted of five samples, including microsatellite-stable and MSI tumor tissues. The sample panels were coded at random, and the returned results were compared and scored. RESULTS: The fully validated sample panels showed appropriate applicability with commercially available assays. There were eight false-negative results in 2021 and five false results (two false-positives and three false-negatives) in 2022. Among the participating laboratories, in 2021, 20 (74.07%) provided completely correct results; in 2022, 38 (92.68%) obtained an optimal score. CONCLUSION: The molecular detection of MSI in China exhibited an improvement in a 2-year EQA study. Participation in EQA program is an efficient way of assessing the performance of laboratories and improving their ability.

External quality assessment for detection of methylated Syndecan 2 (SDC2) in China.

OBJECTIVES: Detection of Syndecan 2 (SDC2) methylation in stool DNA is a novel method for the auxiliary diagnosis of early colorectal cancer (CRC). Currently, this method has been widely applied; however, its accuracy and reliability have not been determined. The objective of this pioneering study was to evaluate the performance of clinical laboratories in China for their ability to detect SDC2 methylation from stool DNA. METHODS: We generated a sample panel consisting of clinical and cell samples. The clinical samples were stool specimens from patients with or without CRC, including four positives (prepared by serial dilution from one stool specimen), one negative and one interferential sample. Two cell samples, with positive or negative methylated SDC2, were used as controls. The panel was distributed to 32 clinical laboratories for analysis of SDC2 methylation, and the results were compared and scored. RESULTS: The sample panel was compatible with commercially available assays and it showed appropriate stability to be an external quality assessment material. There were four false results; one hospital laboratory and one commercial diagnostic laboratory had a false-positive and a false-negative result, respectively, and one commercial diagnostic laboratory had both a false-positive and false-negative result. Among the 32 participating laboratories, 29 (90.62%) obtained an acceptable or better performance score, while 3 (9.38%) laboratories required improvement. CONCLUSIONS: Our results demonstrate that the detection of SDC2 methylation from stool DNA was satisfactory in China. Additionally, the importance of external quality assessment was highlighted for monitoring the performance of clinical laboratories.

Post-failure behavior analysis of the Shenzhen "12.20" CDW landfill landslide.

Since the 1990s, with rapid economic development and urbanization occurring in many countries, the amount of construction and demolition waste (CDW) has also increased. Landfills have become the most commonly used method of disposing of CDW. The safety of landfill slopes is very important. On December 20, 2015, a catastrophic landslide occurred in Shenzhen, Guangdong, Southeastern China. Seventy-seven people were killed, and 33 buildings were buried or damaged. In this paper, the Shenzhen 12.20 landslide is used as an example, and the characteristics of the landfill landslide's post-failure behavior are studied. The following conclusions are made: (1) According to our field investigations, the landslide's motion can be divided into the source area, the propagation area, and the accumulation area. During post-failure motion, loose saturated spoil, which experiences motion similar to that of a slurry flow, and water are the critical factors that cause slope failure and result in a long runout slide. (2) The DAN3D analysis method can satisfactorily reproduce the motion of the Shenzhen "12.20" landslide. (3) A Frictional model can be used for the simulation analysis of the source area. In addition, the Bingham model can be used for the fluidization simulation analysis of the propagation and accumulation areas of a CDW landslide. These conclusions can be used for scientific analysis of CDW landfill landslide hazard zoning and early monitoring and warnings.

External quality assessment for human papillomavirus 16/18 DNA detection and genotyping in Shanghai, China.

BACKGROUND: Human papillomavirus (HPV) DNA detection and genotyping is now being used for cervical screening by a growing number of laboratories in Shanghai, but they may have various levels of proficiency. The objective of this study was to evaluate the performance of clinical laboratories for HPV DNA detection and genotyping by an external quality assessment (EQA) program. METHODS: The EQA panels were clinically validated by the Cobas 4800 HPV test, and then distributed to the participating laboratories in May 2015 (round 1) and September 2015 (round 2). Each panel consisted of one negative sample and nine positive cell or clinical samples of HPV16 and HPV18 types at different concentrations. In total, 40 laboratories submitted 18 qualitative and 22 genotyping data sets in round 1 and 44 laboratories submitted 18 qualitative and 26 genotyping data sets in round 2. In both rounds, all laboratories used commercial assays. RESULTS: The negative samples were detected correctly in both rounds by all participating laboratories. There were no false-positive results in the qualitative data sets and only two false-positive results in the genotyping data sets in each of round 1 and round 2. The false-negative rates were 8.0% for round 1 and 2.7% for round 2. For the qualitative data sets, almost all of the laboratories (100% for round 1 and 97.8% for round 2) obtained a score of acceptable or better. For the genotyping results, acceptable or better scores were obtained in 81.8% (round 1) and 100% (round 2). CONCLUSIONS: Our results indicate that the majority of laboratories in Shanghai have reliable diagnostic ability for HPV detection and genotyping. Moreover, this study emphasizes the importance of EQA for monitoring the performance of clinical laboratories.

Long-term effects of methadone maintenance treatment with different psychosocial intervention models.

This study evaluated the long-term effects of different psychosocial intervention models in methadone maintenance treatment (MMT) in Xi'an China. Patients from five MMT clinics were divided into three groups receiving MMT only, MMT with counseling psychology (CP) or MMT with contingency management (CM). A five-year follow-up was carried out with daily records of medication, monthly random urine morphine tests, and tests for anti-HIV and anti-HCV every six months. Drug use behavior was recorded six months after initial recruitment using a survey. Adjusted RRs and their 95% confidence intervals (CIs) were estimated using an unconditional logistic regression model or a Cox proportional hazard model. A total of 2662 patients were recruited with 797 in MMT, 985 in MMT with CP, and 880 in MMT with CM. Following six months of treatment, the injection rates of MMT with CP and MMT with CM groups were significantly lower than that of MMT (5.1% and 6.9% vs. 16.3%, x²  =  47.093 and 29.908, respectively; P<0.05). HIV incidences for MMT, MMT with CP and MMT with CM at the five year follow-up were 20.09, 0.00 and 10.02 per ten thousand person-years, respectively. HCV incidences were 18.35, 4.42 and 6.61 per hundred person-years, respectively, demonstrating that CP and CM were protective factors for HCV incidence (RR  =  0.209 and 0.414, with range of 0.146-0.300 and 0.298-0.574, respectively). MMT supplemented with CP or CM can reduce heroin use and related risk behaviors, thereby reducing the incidence of HIV and HCV.

A study of 6-year retention in methadone maintenance treatment among opioid-dependent patients in Xi'an.

OBJECTIVE: We analyzed a 6-year methadone maintenance treatment (MMT) retention rate in 8 MMT clinics in Xi'an and the factors that influenced the retention rate. METHODS: We conducted a 6-year retrospective dynamic cohort study of 5849 eligible patients from 2006 to 2011. Participants were serially enrolled on the basis of opioid addiction, age, residence status, and civil capacity. Cumulative retention in treatment was calculated using survival analyses (life tables) on the basis of the number of days in MMT. We also used the Cox proportional hazard regression model to analyze the factors that may influence treatment retention. RESULTS: The MMT retention varied from a less than 1 month to a maximum of 71.2 months; the average dose was 48.76 ± 17.03 mg/d. The cumulative retention for 12, 24, 36, 48, 60, and 72 months after MMT initiation were 0.87, 0.76, 0.66, 0.57, 0.49, and 0.43, respectively. The MMT retention rate was significantly associated with factors that included the particular clinic for MMT, the year when the subject initiated MMT, average daily dose, hidden drug use, sex, age, length of drug abuse history, needle sharing, living arrangements, and employment status. CONCLUSIONS: The 6-year retention rates for MMT in the 8 clinics in Xi'an were higher than those reported in other studies of other clinics. High therapeutic doses (>60 mg/d) could reduce the risk of patients withdrawing from treatment. Retention rates were relatively high in cohorts who were elderly, living with family, employed, or drug users, especially those with a long history of drug abuse.

A cost-effectiveness analysis of universal childhood hepatitis A vaccination in China.

The socioeconomic improvement has impacted hepatitis A virus (HAV) infection with a shift from high to intermediate endemicity in many parts of China. The first China-developed inactivated hepatitis A vaccine, with significantly low price, was licensed in 2002, prompting us to evaluate whether universal childhood vaccination is advisable now in China. We considered vaccination scheduled at ages 12 and 18 months for all healthy children, and assumed that a single cohort was enrolled in 2005. A Markov model was used to predict hepatitis A outcomes and costs. Vaccination was compared with no vaccination, and the cost-effectiveness of vaccination was evaluated from the health system and the societal perspectives. The analysis was run separately in five regions (covering all the 31 provinces of Mainland China) defined by anti-HAV prevalence (around 50%, 50-69%, 70-79%, 80-89% and 90%-). The study projects that with the Chinese low-cost vaccine, vaccination could gain quality adjusted life years (QALYs) through the whole country and save health system or societal costs in the lowest, lower, intermediate and higher infection regions. Vaccination should also be cost-effective in the highest infection region because of low additional costs per QALY gained. However, vaccination would increase the probability of death due to hepatitis A in the highest and higher infection regions by 38 and 37 per million enrolled, respectively, and as vaccine protection loss increases the risk would also occur in intermediate and lower infection regions. The trend that the lower infection level the region has, the more cost-effective vaccination would be is obvious. Sensitivity analyses prove that our conclusions are robust. Considering the potential risk of vaccination, as well as unbalanced socioeconomic developments and significant differences in HAV infection through the whole country, the study suggests that universal childhood hepatitis A vaccination should be first administrated in provinces with the lowest infection level. With knowledge accumulation and further evaluations, the zone of immunization would be considered to be expanded gradually from provinces with lower infection level to those with higher.