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Standardization of Nucleic Acid Tests: the Approach of the World Health Organization.

ABSTRACT: The first World Health Organization (WHO) international standards (ISs) for nucleic acid amplification techniques were established two decades ago, with the initial focus on blood screening for three major viral targets, i.e., hepatitis C virus, hepatitis B virus, and human immunodeficiency virus 1. These reference materials have subsequently found utility in the diagnosis and monitoring of a wide range of infectious diseases in clinical microbiology laboratories worldwide. WHO collaborating centers develop ISs and coordinate international studies for their evaluation. The WHO Expert Committee on Biological Standardization is responsible for the endorsement of new standardization projects and the establishment of new and replacement ISs. Potencies of ISs are defined in international units (IU); the reporting in IU for assays calibrated with an IS (or secondary standards traceable to the IS) facilitates comparability of results for different assays and determination of assay parameters such as analytical sensitivities.

SUBMITTER: Baylis SA

PROVIDER: S-EPMC6322456 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Standardization of Nucleic Acid Tests: the Approach of the World Health Organization.

Baylis S A SA Wallace P P McCulloch E E Niesters H G M HGM Nübling C M CM

Journal of clinical microbiology 20190102 1

The first World Health Organization (WHO) international standards (ISs) for nucleic acid amplification techniques were established two decades ago, with the initial focus on blood screening for three major viral targets, i.e., hepatitis C virus, hepatitis B virus, and human immunodeficiency virus 1. These reference materials have subsequently found utility in the diagnosis and monitoring of a wide range of infectious diseases in clinical microbiology laboratories worldwide. WHO collaborating cen ...[more]

PMID: 30257900

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Project description:BackgroundResearch in 2007 showed that World Health Organization (WHO) recommendations were largely based on expert opinion, rarely used systematic evidence-based methods, and did not follow the organization's own "Guidelines for Guidelines". In response, the WHO established a "Guidelines Review Committee" (GRC) to implement and oversee internationally recognized standards. We examined the impact of these changes on WHO guideline documents and explored senior staff's perceptions of the new procedures.Methods and findingsWe used the AGREE II guideline appraisal tool to appraise ten GRC-approved guidelines from nine WHO departments, and ten pre-GRC guidelines matched by department and topic. We interviewed 20 senior staff across 16 departments and analyzed the transcripts using the framework approach. Average AGREE II scores for GRC-approved guidelines were higher across all six AGREE domains compared with pre-GRC guidelines. The biggest changes were noted for "Rigour of Development" (up 37.6%, from 30.7% to 68.3%) and "Editorial Independence" (up 52.7%, from 20.9% to 73.6%). Four main themes emerged from the interviews: (1) high standards were widely recognized as essential for WHO credibility, particularly with regard to conflicts of interest; (2) views were mixed on whether WHO needed a single quality assurance mechanism, with some departments purposefully bypassing the procedures; (3) staff expressed some uncertainties in applying the GRADE approach, with departmental staff concentrating on technicalities while the GRC remained concerned the underlying principles were not fully institutionalized; (4) the capacity to implement the new standards varied widely, with many departments looking to an overstretched GRC for technical support.ConclusionsSince 2007, WHO guideline development methods have become more systematic and transparent. However, some departments are bypassing the procedures, and as yet neither the GRC, nor the quality assurance standards they have set, are fully embedded within the organization.

Project description:BACKGROUND:To examine cross-national patterns and correlates of lifetime and 12-month comorbid DSM-IV anxiety disorders among people with lifetime and 12-month DSM-IV major depressive disorder (MDD). METHOD:Nationally or regionally representative epidemiological interviews were administered to 74 045 adults in 27 surveys across 24 countries in the WHO World Mental Health (WMH) Surveys. DSM-IV MDD, a wide range of comorbid DSM-IV anxiety disorders, and a number of correlates were assessed with the WHO Composite International Diagnostic Interview (CIDI). RESULTS:45.7% of respondents with lifetime MDD (32.0-46.5% inter-quartile range (IQR) across surveys) had one of more lifetime anxiety disorders. A slightly higher proportion of respondents with 12-month MDD had lifetime anxiety disorders (51.7%, 37.8-54.0% IQR) and only slightly lower proportions of respondents with 12-month MDD had 12-month anxiety disorders (41.6%, 29.9-47.2% IQR). Two-thirds (68%) of respondents with lifetime comorbid anxiety disorders and MDD reported an earlier age-of-onset (AOO) of their first anxiety disorder than their MDD, while 13.5% reported an earlier AOO of MDD and the remaining 18.5% reported the same AOO of both disorders. Women and previously married people had consistently elevated rates of lifetime and 12-month MDD as well as comorbid anxiety disorders. Consistently higher proportions of respondents with 12-month anxious than non-anxious MDD reported severe role impairment (64.4 v. 46.0%; ? 2 1 = 187.0, p < 0.001) and suicide ideation (19.5 v. 8.9%; ? 2 1 = 71.6, p < 0.001). Significantly more respondents with 12-month anxious than non-anxious MDD received treatment for their depression in the 12 months before interview, but this difference was more pronounced in high-income countries (68.8 v. 45.4%; ? 2 1 = 108.8, p < 0.001) than low/middle-income countries (30.3 v. 20.6%; ? 2 1 = 11.7, p < 0.001). CONCLUSIONS:Patterns and correlates of comorbid DSM-IV anxiety disorders among people with DSM-IV MDD are similar across WMH countries. The narrow IQR of the proportion of respondents with temporally prior AOO of anxiety disorders than comorbid MDD (69.6-74.7%) is especially noteworthy. However, the fact that these proportions are not higher among respondents with 12-month than lifetime comorbidity means that temporal priority between lifetime anxiety disorders and MDD is not related to MDD persistence among people with anxious MDD. This, in turn, raises complex questions about the relative importance of temporally primary anxiety disorders as risk markers v. causal risk factors for subsequent MDD onset and persistence, including the possibility that anxiety disorders might primarily be risk markers for MDD onset and causal risk factors for MDD persistence.

Project description:Sepsis is a serious medical condition requiring timely administered, appropriate antibiotic therapy. Blood culture is regarded as the gold standard for aetiological diagnosis of sepsis, but it suffers from low sensitivity and long turnaround time. Thus, nucleic acid amplification tests (NAATs) have emerged to shorten the time to identification of causative microbes. The aim of the present study was to evaluate the clinical utility in everyday practice in the emergency department of two commercial NAATs in patients suspected with sepsis.During a six-week period, blood samples were collected consecutively from all adult patients admitted to the general emergency department for suspicion of a community-onset sepsis and treated with intravenous antibiotics. Along with conventional blood cultures, multiplex PCR (Magicplex™) was performed on whole blood specimens whereas portions from blood culture bottles were used for analysis by microarray-based assay (Prove-it™). The aetiological significance of identified organisms was determined by two infectious disease physicians based on clinical presentation and expected pathogenicity.Among 382 episodes of suspected sepsis, clinically relevant microbes were detected by blood culture in 42 episodes (11%), by multiplex PCR in 37 episodes (9.7%), and by microarray in 32 episodes (8.4%). Although moderate agreement with blood culture (kappa 0.50), the multiplex PCR added diagnostic value by timely detection of 15 clinically relevant findings in blood culture-negative specimens. Results of the microarray corresponded very well to those of blood culture (kappa 0.90), but were available just marginally prior to blood culture results.The use of NAATs on whole blood specimens in adjunct to current culture-based methods provides a clinical add-on value by allowing for detection of organisms missed by blood culture. However, the aetiological significance of findings detected by NAATs should be interpreted with caution as the high analytical sensitivity may add findings that do not necessarily corroborate with the clinical diagnosis.

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Standardization of Nucleic Acid Tests: the Approach of the World Health Organization.

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Standardization of Nucleic Acid Tests: the Approach of the World Health Organization.

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