Pilot Assessment of a Rapid Test for the Detection of COVID-19 Disease by Using Latex Agglutination

Research Article

Austin J Clin Case Rep. 2021; 8(8): 1224.

Pilot Assessment of a Rapid Test for the Detection of COVID-19 Disease by Using Latex Agglutination

Cariaga-Martínez A1*, Gutiérrez KJ1 and Alelú-Paz R1,2*

1Laboratory of Neuroscience Elena Pessino Gómez del Campo, Madrid Scientific Park, Spain

2Department of Psychology, Universidad Francisco de Vitoria, Madrid, Spain

*Corresponding author: Alelú-Paz R, Department of Psychology, Universidad Francisco de Vitoria. Ctra. Pozuelo-Majadahonda KM 1.800. ZIP: 28223. Pozuelo de Alarcón, Madrid, Spain

Cariaga-Martínez A, Laboratory of Neuroscience Elena Pessino Gómez del Campo, Madrid Scientific Park, ZIP: 28049. Madrid, Spain

Received: June 08, 2021; Accepted: June 30, 2021; Published: July 07, 2021


The rapid spread of the SARS-CoV-2 virus, which was declared a pandemic by the WHO in March 2020, has forced the scientific community to develop rapid detection tests in order to detect positive cases and implement the containment measures established in each country. In this regard, the techniques used (RTPCR, antibody test, etc.) have a number of drawbacks: require specialized personnel, in addition to, in some cases, obtaining results after 24 hours. Agglutination tests, widely used in the detection of viral particles, represent a simple, inexpensive and scalable method that would allow screening studies to be carried out in large populations. In this paper, we present a SARS-CoV-2 detection test based on this methodology, which could be considered as a complementary method to the techniques used for the detection of SARSCoV-2.

Keywords: COVID-19; SARS-CoV-2; Diagnosis; Rapid test; Agglutination


The pandemic declared by WHO in March 2020 has resulted in thousands of deaths and a large expenditure of money in the development of rapid detection tests [1]. Initially, serological tests were used to assess the presence of infection although real-time PCR quickly established itself as a gold standard method [2]. Antigen tests were developed well into the pandemic and were blamed for lack of sensitivity and specificity. Nowadays, antigen tests have become popular, but their processing can only be carried out by competent healthcare personnel. In this sense, the dynamics of the pandemic has forced us to develop self-administered tests that allow us to obtain results in a very short time, in order to detect positive cases and implement the control measures established in each of the countries. As we have previously evaluated, one of the main difficulties in detecting the presence of SARS-CoV-2 infection is the technical difficulty in applying them (high costs and the need for highly qualified technical personnel), which makes it impossible to administer this type of test on a massive scale for screening studies. In this respect, the agglutination test is a simple, one-step method used for the detection of viral antigens in clinical specimens [3,4]. These assays are based on the initial fixation of specific antiviral antibodies on erythrocytes or latex particles which allows incubation with the clinical sample in which the antigen is being investigated and the particles agglutinate if the appropriate antigen is present. Although these tests require to use other techniques in order to confirm the results, due to the high percentage of nonspecific reactions, they can be used for screening studies in very large populations [5].

In this pilot test, we evaluated the technical and performance characteristics of a rapid SARS-CoV-2 detection test by using this methodology, that is, latex beads agglutination for application as an inexpensive, scalable, and complementary method of COVID-19 detection.

Materials and Methods


Sixty samples were obtained from persons that presented to the Emergency Department of the Hospital Puerta de Hierro- Majadahonda in Madrid (Spain), with suspected SARS-CoV-2 infection, with presence or absence of symptoms. The patients were randomly selected, informed of the existence of a pilot trial and were asked to participate. All the enrolled patients received the appropriate information and signed the informed consent in accordance with the regulations for studies with human samples. The present study was positively evaluated and approved by the Hospital’s Bioethics Committee.


Saliva samples were collected after signing the informed consent and consisted of spontaneously generated saliva (at least 0.2ml) that was collected in sterile tubes and kept at -80°C until final processing. The Emergency Department and the Biobank Unit from the Hospital Universitario Puerta de Hierro Majadahonda assisted in the collection and preservation of the samples.

Real-time PCR

Patients’ samples were assessed by using the following Real-time PCR kits:

• Lyophilized 1-step RT-PCR Polymerase Mix (TIB MOLBIOL. Cat.- No. 90-9999-96).

• As an extraction control PCR (to verify the presence of amplifiable nucleic acids): LightMix Modular EAV RNA Extraction Control (Roche. Cat.- No. 66-0909-96).

• To detect SARS and SARS-CoV-2: LightMix Modular SARS-CoV (COVID19) E-gene (Roche. Cat. No.- 53-0776-96).

Briefly, the FastCycle Protocol: (Table 1).