All of them contributed to writing the article and approved to submit for publication. key role in COVID-19 diagnosis. These tests can be applied for suspected false-negative RT-PCR results and for individual determination of response. The use of these assessments can also contribute greatly to public health strategies, such as population screening and supporting vaccination planning. Serological status for high-affinity antibodies (both IgM and IgG) should be performed ideally 21 days after potential infectious contact, given that the majority of uncovered individuals will have seroconverted. strong class=”kwd-title” Keywords: COVID-19, Diagnosis, Serological test, High-affinity antibodies, RT-PCR Introduction In December 2019, atypical pneumonia cases caused by a new coronavirus were identified in Wuhan, a city of Hubei Province in China (Zhu et al., 2020). Within days, the virus had spread, resulting in an epidemic throughout China (The Novel Coronavirus Thevetiaflavone Pneumonia Emergency Response Epidemiology Team, 2020). An increasing number of cases were reported in countries around the world in the ensuing weeks (WHO, 2020b). In February 2020, the World Health Organization (WHO) named the disease as COVID-19, which stands for coronavirus disease 2019 (WHO, 2020c). The virus that causes COVID-19 was then named as Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) (Coronaviridae Study Group of the International Committee on Taxonomy of Viruses, 2020). COVID-19 has since been declared a global pandemic (Cucinotta and Rabbit Polyclonal to FIR Vanelli, 2020), with 15,301,530 cases worldwide and 625,005 deaths globally. Thevetiaflavone In the Americas, the numbers are also staggering: 11,667,196 confirmed cases with 419,995 deaths (as of August 17th, 2020) (PAHO, 2020). The initial stage involves an incubation period when SARS-CoV-2 multiplies and establishes itself mainly in the respiratory system. During the second stage, localized inflammation can occur in the lungs. Thevetiaflavone The third (and most severe) stage of the disease can cause the syndrome of extrapulmonary systemic hyperinflammation (Siddiqi and Mehra, 2020). RT-PCR is usually a test for diagnosing COVID-19, based on nasopharyngeal swab samples or other upper respiratory tract samples (Wang et al., 2020b). In symptomatic individuals, viral RNA can be detectable early on day one of symptoms and culminate within the first week of symptom onset. By week three, positivity of the test for detecting viral RNA starts to decline (Sethuraman et al., 2020). A downside of this sample collection approach involves false-negative results, largely due to inappropriate timing of sample collection relative to illness onset and poor sampling technique, especially for nasopharyngeal swabs. Given that the design for the RT-PCR test is based on the genome sequence of SARS-CoV-2, its specificity is almost 100%, with few false-positive results (Sethuraman et al., 2020). Another diagnostic tool for detecting SARS-CoV-2 infection is usually serological testing which evaluates the host immune response (Loeffelholz and Tang, 2020). It is essential for patients with moderate to moderate illness who may present two weeks after illness onset. Serological diagnosis is also becoming an important tool to help understand the extent of COVID-19 in the community (Sethuraman et al., 2020). Antibodies start to increase from the second week of symptom onset, constituting the earliest and most sensitive serological marker, with IgM and IgG levels peaking in the second and third weeks of illness. Subsequently, IgM decreases by week 5, while IgG remains high beyond 7 weeks (Sethuraman et al., 2020). These findings together with the plethora of available testing methodologies (CDC, 2020b, Loeffelholz and Tang, 2020), evolving knowledge around the behavior of the virus, and the complexity of the human immune response, have led to the need for guidance on how to use and appropriately interpret results of the available assessments. As the pandemic progresses, it has become clear that the primary transmission pathway is usually through respiratory aerosols Thevetiaflavone (Bahl et al., 2020) as well as through direct contact of eyes, nose, or mouth with contaminated surfaces (Ong et al., 2020). The virus has also been detected in nonrespiratory samples such as stools, urine, blood, ocular secretions, and semen (Wang et al., 2020b). The risk of transmission of SARS-CoV-2 from an infected person to another appears to vary and depends on the type and duration of exposure, use of preventive measures, and other individual factors (Rosenberg et al., 2020). Latin America is usually a large and heterogeneous territory, including well-developed and poor areas with limited resources, in which the pandemic rapidly spreads..