Academic journal article Bulletin of the World Health Organization

A Guide to Aid the Selection of Diagnostic tests/Guide Destine a Faciliter le Choix Des Tests diagnostiques/Manual De Ayuda Para la Seleccion De Pruebas De Diagnostico

Academic journal article Bulletin of the World Health Organization

A Guide to Aid the Selection of Diagnostic tests/Guide Destine a Faciliter le Choix Des Tests diagnostiques/Manual De Ayuda Para la Seleccion De Pruebas De Diagnostico

Article excerpt

Introduction

Diagnostic testing has become indispensable for diagnosing and monitoring disease, for providing prognoses and for predicting treatment responses. (1,2) Today, over 40 000 products are available globally for the in vitro diagnostic testing of a wide range of conditions. (3) These include traditional laboratory-based tests, with samples being sent to a central laboratory for analysis, and point-of-care tests, which can be performed near, or at, the point of patient care. Point-of-care testing can help optimize treatment decision-making, avoid referrals, improve the efficiency of care and decrease costs, especially in resource-constrained settings where laboratory infrastructure is weak. (4)

In the early 1990s, the first point-of-care tests for use in resource-constrained settings became commercially available: lateral flow immunoassays (often called rapid diagnostic tests) for the diagnosis of malaria. (5,6) These assays are now well established and have replaced blood film microscopy in many settings. However, as the market for diagnostic tests has increased, the choice has become overwhelming for some diseases: in 2015, the World Health Organization (WHO), the Foundation for Innovative New Diagnostics (FIND) and the Centers for Disease Control and Prevention (CDC) in the United States of America reviewed approximately 250 different diagnostic tests for malaria. (7) We conducted an online market search for screening tests for hepatitis C virus infection and identified more than 50 products, and UNITAID's 2015 report on tuberculosis diagnostics highlighted the increasing complexity of the market, (8) with WHO endorsing (though not prequalifying) several products in recent years. (9-12) In some cases, a single manufacturer may hold a monopoly, which can lead to high costs. Conversely, diagnostic and monitoring tests for neglected diseases, such as visceral leishmaniasis, human African trypanosomiasis, chikungunya, dengue and brucellosis, remain scarce. (13,14)

With the increase in the number of in vitro diagnostic tests has come an increase in the number of guidelines and recommendations, together with countless publications on their performance and implementation. (7,13,15-17) However, this wealth of material covers only a small proportion of commercially available tests. In our experience, the information available on many tests is limited and there is often a lack of independent data on a test's performance and on whether the manufacturing process is reliable enough to ensure consistent quality across multiple lots. Both the quantity and the variable quality of the information available make it difficult for policymakers, laboratories and other end-users to make rational decisions about the selection and use of these tests. (18,19) As a result, tests have been used unnecessarily and incorrectly and results have been misinterpreted. (20-23)

Given these difficulties, the process of selecting one or several tests for use in a diagnostic algorithm can be cumbersome for clinics, countries and nongovernmental organizations providing medical support. (19) The nongovernmental organization, Medecins Sans Frontieres, operates or supports health ministry laboratories in more than 40 countries. Currently, the organization has over 15 laboratory advisors at its headquarters and more than 100 staff working in laboratories around the world. The amount of laboratory equipment and the number of in vitro diagnostic tests used by Medecins Sans Frontieres itself have almost doubled in the past 10 years and the organization has encountered numerous challenges in selecting and implementing tests for its projects.

In this article, we outline a six-step approach to overcoming the obstacles encountered by Medecins Sans Frontieres in selecting and implementing in vitro diagnostic tests. This approach was derived from a review of the diagnostics literature and from our experience with implementing diagnostics programmes. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.