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The role of the LNS in COVID19 National Testing Strategy

The role of the LNS in COVID19 National Testing Strategy
2021 12-01

The international landscape of the evolution of the COVID19 pandemic had shown a new wave of COVID19 this autumn with health authorities worldwide addressing the new wave. The Department of Microbiology is contributing to the national strategy by providing specialised RT-PCR testing, serology testing, in addition to its sequencing services. The testing activities are led by Dr. Nguyen-Trung Nguyen and Dr. Tamir Abdelrahman and coordinated by Nicolas Van Elsué. They form part of the activities of the national reference laboratory for acute respiratory infection in our department that started on 20th September and will continue until 31st December 2021. The main activities are:

  • Long-term care facilities;

LNS deploys nine outreach teams, each composed of one administrator and one nurse to perform systematic RT-PCR testing in the nursing homes. The visits are planned in 3-week cycle. There will be an urgent intervention team, when a cluster is identified by Inspection Sanitaire. The systematic testing is complementary to frequent rapid diagnostic testing using antigen detection tests introduced earlier this year.

  • National COVID19 Seroeprevalence program;

Serological testing is performed upon invitation to monitor the seroprevalence of anti-SARS-CoV-2 antibodies in the population. Individuals will be invited to one of the three DBS Centers;

1. Centre de Prélèvement (CDP) LNS,

2. Maison Médicale Val Fleuri Luxembourg,


3. Maison Médicale Ettelbruck.

  • School Testing;

The Ministry of Education is adjusting its testing strategy in schools, as the PCR testing will target primary schools as the younger population (< 12 years old) are not vaccinated yet. We currently deploy 12 teams working on the school testing.

  • The national program “COVID19 vaccination Serology follow up – COVVAC Sero” (COVVAC SERO);

The program was launched on June 15th 2021 to evaluate the development of antibodies post-vaccination and to create a national database for vaccination follow-up in nursing homes. We are currently running the second wave. For the sampling, a less invasive method, the Dry Blood Spot (DBS) test, was chosen. The advantage of this test is, that patients are only required to provide a few drops of blood. The first wave report is currently under final revision.

Serving country and people with Passion

A clinical outreach unit was established for the first time within the department of Microbiology with the objective to provide a clinical liaison between LNS and its clinical partners. The COVID19 pandemic had added another mission to the unit which is direct testing activities involving sample collection either from dedicated sample centers or on the field via school testing program and nursing home initiatives. The nature of the operation brought the Together LNS attitude into action. Close coordination was orchestrated by the LNS’ director Prof. Dr. Friedrich Mühlschlegel, our Finance and administrative department, the Department of Medical Biology, legal adviser and the Communication office as well as various individuals contributed to the activities at various levels.

The passion of caring for the country and its people has empowered this project. Our partners have been going the extra mile as well, as for the second year, we continue the school testing in collaboration with the “Ministère de l’Éducation nationale, de l’Enfance et de la Jeunesse”, the Ministry of Education, Children and Youth, and the various directorates of basic education. The perfect understanding and work flow we established is a model for successful inter-institutional projects. We had similar experience working with the Ministry of Family and the directors of nursing homes, supervised accommodating structures and elderly residencies.

Implementation of state-of-the-art diagnostic solutions

Since the introduction of the national vaccination campaign, there is a rising need to evaluate the impact of this national intervention. The LNS’s department of Microbiology has hence launched a national program (COVID19 vaccination Serology follow up – COVVAC Sero). In the framework of this program, the Virology service carried out serological testing for residents and staff in nursing homes to evaluate the development of antibodies post-vacciantion. This will allow building a national database for the vaccination follow-up. The goal is to test interested individuals from the 66 different nursing homes in Luxembourg every 3 months to establish their antibody levels and to evaluate the effectiveness of the different types of vaccines that are currently used against the different SARS-CoV-2 variants.

Our Virology service developed a semi-quantitative ELISA method to assign an index that corresponds to a certain level of immunity. For example, an index value of three corresponds to the moderate presence of IgG antibodies against the SARS-CoV-2 virus (40-60% NA). The technique became the first complete automated workflow in our department in alignment with our paperless lab in 2022 initiative.

Our technical officer, Dr. Tanja Lepore, and Lab technicians, Allan Muller and João Araújo, recorded a video to demonstrate how to perform the sampling process. Nicolas Van Elsué worked in close contact with the LNS’ communication department to produce a demonstrative video.


Table 1 The cumulative COVID19 outreach testing activities by the Microbiology department at LNS since 20/09/2021