PPubMed19 May 2021Cited 7×

Evaluation of Triage Tests When Existing Test Capacity Is Constrained: Application to Rapid Diagnostic Testing in COVID-19

Janet Bouttell, Neil Hawkins

Abstract

In this article, we set out a method of applying quantitative measures such as sensitivity and specificity, as stated in documents such as WHO TPPs, to particular diseases and local contexts to provide more meaningful metrics to decision makers. We use antigen tests for SARS-CoV-2 as examples to demonstrate that, if facilities for reference testing are restricted, there may be a role for RDTs to be used as triage tests to enrich the prevalence of disease in the population tested using the reference test and improve the efficiency of the laboratory-based RNA testing process. This allows a great

A figure from Evaluation of Triage Tests When Existing Test Capacity Is Constrained: Application to Rapid Diagnostic Testing in COVID-19 — fig. from the paper

§ The Valyu brief

The paper, in five minutes

Read from the full text via Valyu Contents

When the availability of the reference test is constrained, tests added in a triage position do not need high levels of accuracy to increase the number of cases diagnosed.

What’s new

i.Developed a simple decision‑analytic model incorporating prevalence, sensitivity, specificity, and reference‑test capacity.
ii.Applied the model to a case study of rapid antigen tests for SARS‑CoV‑2 using data from 425 samples.
iii.Demonstrated how test specificity and sensitivity affect population coverage and case identification under constrained and unconstrained reference‑test capacity.

How they did it

We developed a decision‑analytic model with inputs of prevalence, sensitivity, specificity and reference test capacity. The model was illustrated with a case study of rapid diagnostic antigen tests for SARS‑CoV‑2, using performance data from an evaluation of 425 samples from the United Kingdom and Germany.

What they found

A rule‑in triage test (high specificity) yielded a 39.1% probability of a positive reference test after triage, versus 9.2% for a rule‑out test.
When reference test capacity is constrained, the relative expansion of the tested population and cases identified is greater with a high‑specificity triage test.
In the unconstrained scenario, the high‑specificity rule‑in test reduces the number of reference tests required the most but also results in the greatest number of missed cases.
Base‑case prevalence was set at 5% for the case study analyses.
The evaluated study population had a SARS‑CoV‑2 prevalence of just under 2%.

Caveats

✕The models are simplified and are not intended to provide definitive estimates of clinical value and cost‑effectiveness.
✕Using the model outcomes for decision making requires assumptions that may limit their applicability.
✕Results depend on disease prevalence and test performance, which can vary across settings.

§ The Valyu brief

Reading the full paper and taking notes. This takes a few seconds…

§ Ask this paper

Ask a question about this paper

Valyu reads the full text and answers from what the paper actually says.

§ Related work in other archives

Evaluation of Triage Tests When Existing Test Capacity Is Constrained: Application to Rapid Diagnostic Testing in COVID-19

The paper, in five minutes

Ask a question about this paper

Similar papers in all four archives

Similar papers in all four archives

The paper, in five minutes