Evaluation of Antibacterial Activity of Bismuth Ferrites Nanoparticles in the inhibition of E. coli and S. aureus bacteria.

In this work, bismuth ferrites (BFO) nanoparticles were produced in the form of using sol-gel technique, followed by annealing in a tube furnace in temperatures from 400 °C to 650 ºC. X-ray diffraction (XRD) results showed the formation of small sizes nanoparticles (NPs) with high purity. Structural analysis displayed that annealing at 600 ºC could make BFO NPs be fitted to rhombohedral space group (R3c), with small quantity of spurious phases. The sizes of the BFO nanoparticles determined by transmission electron microscopy (HRTEM) are between 50 to 100 nm. To evaluate the efficiency of BFO in antimicrobial susceptibility tests, the nanoparticles were dispersed through nanoemulsion and tested agar diffusion method and dilution in a 96 well plate using a Gram positive strains (Staphylococcus aureus) and Gram negative strain (Escherichia coli). The antibacterial activity of the BFO NPs was partially tested at concentrations of 2 mg/mL with MIC greater than 60 µg/mL for both bacteria.

Rocio Virus: An Updated View on an Elusive Flavivirus.

Rocio virus (ROCV) is a mosquito-borne flavivirus and human pathogen. The virus is indigenous to Brazil and was first detected in 1975 in the Sao Paulo State, and over a period of two years was responsible for several epidemics of meningoencephalitis in coastal communities leading to over 100 deaths. The vast majority of ROCV infections are believed to be subclinical and clinical manifestations can range from uncomplicated fever to fatal meningoencephalitis. Birds are the natural reservoir and amplification hosts and ROCV is maintained in nature in a mosquito-bird-mosquito transmission cycle, primarily involving Psorophora ferox mosquitoes. While ROCV has remained mostly undetected since 1976, in 2011 it re-emerged in Goiás State causing a limited outbreak. Control of ROCV outbreaks depends on sustainable vector control measures and public education. To date there is no specific treatment or licensed vaccine available. Here we provide an overview of the ecology, transmission cycles, epidemiology, pathogenesis, and treatment options, aiming to improve our ability to understand, predict, and ideally avert further ROCV emergence.

Synthesis, characterization, and evaluation of antibacterial activity of transition metal oxyde nanoparticles.

Nanoparticles (NPs) have a wide range of applications in various areas. For health application, cytotoxicity tests are used to ensure its efficiency and safety. In this paper, ZnFe2O4, CoFe2O4, Zn0.5Co0.5Fe2O4 NPs were synthesized, characterized and their antibacterial properties were evaluated. The Sol-Gel method was used to synthesize the NPs. Their electronic and crystallographic structures were characterized by Fourier Transform Infrared Spectroscopy Analysis (FTIR), X-ray fluorescence (XRF), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). To perform the antibacterial evaluation, ferrites were dispersed through nanoemulsion to prevent the crystals from accumulating together. Then the evaluation was performed through microdilution in a 96-well plate and diffusion in agar disc in contact with 3 different strains of Staphylococcus aureus and Escherichia coli. It demonstrated that the Sol-Gel method was efficient to synthesize NPs with suitable sizes for health application. All synthesized NPs showed the inhibition of bacterias with different concentrations used.

First complete genome sequence and molecular characterization of Canine morbillivirus isolated in Central Brazil.

The Brazilian regions are still highly endemic areas for Canine morbillivirus [canine distemper virus (CDV)]. However, little is known regarding the genetic variability of the strain circulating in several Brazilian regions. Here, we report the first full-length genome and molecular characterization of CDV isolated from domestic dogs in the Brazilian Center-West region. Sequence alignment and phylogenetic analyses based on deduced amino acid and nucleotide sequences showed that the isolated strain is characterized as the South America-I/Europe genotype. However, it segregates into a CDV subgenotype branch. Interestingly, both H and F proteins have a gain of a potential N-glycosylation sites compared to the Onderstepoort vaccine strain. Therefore, this study provides a reference to further understand the epidemic and molecular characteristics of the CDV in Brazil.

Serious acute respiratory syndrome: a case series in a municipality region of central Brazil / Síndrome respiratória aguda grave: série de casos em município da região central do Brasil

The influenza B virus is more stable than influenza A, with less antigenic drift and consequent immunologic stability, and does not undergo the process of antigenic shift, its participation in epidemics is minimal, being of lesser academic interest. The aim of this work was to describe the occurrence of a series of SARS cases in a municipality in the Central region of Brazil. This is a case series study with a descriptive and quantitative approach of Serious Acute Respiratory Syndrome (SARS) in institutionalized individuals and a health professional from a long-term institution in the municipality where the study was conducted. The variables studied were: age, comorbidities, vaccination status, date of symptoms onset, symptoms, occurrence of death, information regarding provided care (hospital care, exams, and medications). The study was approved by the Research Ethics Committee of the Federal University of Goiás (UFG), under opinion number 2.167.287. Case 1 was diagnosed with influenza B, treated with antibiotic therapy, with no antiviral drugs administered, and culminated in death. Cases 2 and 3 were confirmed as influenza B, being treated with antiviral drugs and discharged due to full recovery. Case 4 was confirmed as influenza B virus by epidemiological link, treated with antiviral drugs and discharged due to full recovery. An early diagnosis, adequate clinical management, transmissible disease research based on the 11 health promotion steps and actions can promote the reduction of morbimortality by influenza type B.

O vírus influenza B é mais estável que a influenza A, apresenta menor desvio antigênico, consequentemente estabilidade imunológica, e não sofre processo de desvio antigênico, não estão associados a grandes epidemias, estando, portanto, pouco associados ao interesse acadêmico. O objetivo do trabalho foi escrever a ocorrência de uma série de casos de Síndrome Respiratória Aguda Grave (SRAG) em um município da região central do Brasil. Trata-se de um estudo de série de casos com abordagem descritiva e quantitativa de SRAG, ocorridos em indivíduos institucionalizados e um profissional de saúde de uma instituição de longa permanência do município onde o estudo foi desenvolvido. As variáveis estudadas foram: idade, co-morbidades, situação vacinal, data do início dos sintomas, sintomas, ocorrência de óbito, informações referentes à assistência prestada (atendimento hospitalar, exames, medicações). O estudo foi aprovado pelo Comitê de ética em Pesquisa da Universidade Federal de Goiás (UFG), parecer número 2.167.287. O caso 1 foi diagnosticado com influenza B, tratado com antibioticoterapia, não sendo utilizado antiviral, culminando em óbito. O caso 2 e 3 foram confirmados vírus influenza B, sendo tratados com antiviral e receberam alta por cura. O caso 4 foi confirmado influenza por vírus B por vínculo epidemiológico, tratado com antiviral e recebeu alta por cura. Conclusões: Um diagnóstico precoce, manejo clínico adequado, investigação de doenças transmissíveis pautada nos 11 passos e ações de promoção da saúde, podem promover a redução da morbimortalidade por influenza tipo B.

The emergence of SARS, MERS and novel SARS-2 coronaviruses in the 21st century.

At the beginning of the 21st century, a new deadly infectious disease known as severe acute respiratory syndrome (SARS) was recognized as a global public health threat. Subsequently, ten years after the initial SARS cases occurred in 2002, new cases of another atypical respiratory disease caused worldwide concern. This disease became known as Middle East respiratory syndrome (MERS) and was even more lethal than SARS. Currently, history has repeated itself with the emergence of a new Chinese epidemic at the end of 2019. For this respiratory disease, called COVID-19, a novel coronavirus (SARS-CoV-2) was identified as the etiologic agent. In sum, SARS, MERS and COVID-19 are caused by recently discovered coronaviruses that cause flu-like illnesses, but with a clinical outcome that tends to be more severe. As a result of the current importance of coronaviruses in global public health, we conducted a review to summarize and update, above all, the epidemiological historical aspects of the three major diseases in humans caused by coronaviral infection.

Dynamic behavior of Dengue and Zika viruses NS1 protein reveals monomer-monomer interaction mechanisms and insights to rational drug design.

Communicated by Ramaswamy H. Sarma.

Mutation of critical residues reveals insights of yellow fever virus nonstructural protein 1 (NS1) stability and its formation.

Communicated by Ramaswamy H. Sarma.

Prediction of MAYV peptide antigens for immunodiagnostic tests by immunoinformatics and molecular dynamics simulations.

The Mayaro virus is endemic to South America, and the possible involvement of Aedes spp. mosquitoes in its transmission is a risk factor for outbreaks of greater proportions. The virus causes a potentially disabling illness known as Mayaro fever, which is similar to that caused by the chikungunya virus. The cocirculation of both viruses, with their clinical and structural similarities, and the absence of prophylactic and therapeutic measures highlight the need for studies that seek to understand the Mayaro virus. Using approaches in silico, we identified an antigenic and specific epitope (p_MAYV4) in domain A of the E2 glycoprotein of the Mayaro virus. This epitope was theoretically predicted to be stable and exposed on the surface of the protein, where it showed key properties that enable its interaction with neutralizing antibodies. These characteristics make it an interesting target for the development of immunodiagnostic platforms. Molecular dynamics simulation-based structural analysis showed that the PHE95 residue in the E1 fusion loop region is conserved among Alphavirus family members. PHE95 interacts with the hydrophobic residues of the E2 glycoprotein to form a cage-shaped structure that is critical to assemble and stabilize the E1/E2 heterodimer. These results provide important insights useful for the advancement of diagnostic platforms and the study of therapeutic alternatives.

Molecular and serological surveys of canine distemper virus: A meta-analysis of cross-sectional studies.

BACKGROUND: Canine morbillivirus (canine distemper virus, CDV) persists as a serious threat to the health of domestic dogs and wildlife. Although studies have been conducted on the frequency and risk factors associated with CDV infection, there are no comprehensive data on the current epidemiological magnitude in the domestic dog population at regional and national levels. Therefore, we conducted a cross-sectional study and included our results in a meta-analysis to summarize and combine available data on the frequency and potential risk factors associated with CDV infection. METHODS: For the cross-sectional study, biological samples from dogs suspected to have canine distemper (CD) were collected and screened for viral RNA. Briefly, the PRISMA protocol was used for the meta-analysis, and data analyses were performed using STATA IC 13.1 software. RESULTS: CDV RNA was detected in 34% (48/141) of dogs suspected to have CD. Following our meta-analysis, 53 studies were selected for a total of 11,527 dogs. Overall, the pooled frequency of CDV positivity based on molecular and serological results were 33% (95% CI: 23-43) and 46% (95% CI: 36-57), respectively. The pooled subgroup analyses of clinical signs, types of biological samples, diagnostic methods and dog lifestyle had a wide range of CDV positivity (range 8-75%). Free-ranging dogs (OR: 1.44, 95% CI: 1.05-1.97), dogs >24 months old (OR: 1.83, 95% CI: 1.1-3) and unvaccinated dogs (OR: 2.92, 95% CI: 1.26-6.77) were found to be positively associated with CDV infection. In contrast, dogs <12 months old (OR: 0.36, 95% CI: 0.20-0.64) and dogs with a complete anti-CDV vaccination (OR: 0.18, 95% CI: 0.05-0.59) had a negative association. CONCLUSION: Considering the high frequency of CDV positivity associated with almost all the variables analyzed in dogs, it is necessary to immediately and continuously plan mitigation strategies to reduce the CDV prevalence, especially in determined endemic localities.

Epidemiological and clinical profile of HIV-infected patients from Southwestern Goias State, Brazil.

Knowledge about epidemiological distribution patterns of HIV infection in different geographic regions is relevant to understand the dynamics of the disease in Brazil. This study aims to characterize the epidemiological and clinical profile of HIV-infected patients from Southwestern Goias State, from 2005 to 2015. A standardized questionnaire was used to collect clinical-epidemiological, virological, and immunological data from the medical records of all HIV-infected patients (n=539) who were followed at the regional reference center of Jatai, Goias State, Brazil, from 2005 to 2015. We detected the prevalence of male patients and the heterosexual route of transmission, as well as an expressive number of young women infected with HIV. The HIV infection was more prevalent in reproductive ages (55.3%). Most patients presented clinical manifestations related to HIV infection at the time of diagnosis. Twenty-four patients presented coinfection with hepatitis C virus, syphilis, hepatitis B virus, leprosy or Chagas disease. Pneumonia caused by Pneumocystis jirovecii was the most common opportunistic infection, followed by neurotoxoplasmosis, tuberculosis, and neurocryptococcosis. Combined antiretroviral therapy improved CD4+ T-cell counts: the mean CD4+ T-cell counts after treatment was twice as high as those found at the first medical appointment; and highly active antiretroviral therapy promoted viral suppression in a significant number of patients. Considering the increasing distribution of HIV infection to the interior of Brazil, this descriptive study outlines the clinical-epidemiological characteristics of HIV infection in Southwestern Goias and contributes to develop local prevention strategies and public service plans.

The role of mitochondrial DNA damage at skeletal muscle oxidative stress on the development of type 2 diabetes.

Reduced cellular response to insulin in skeletal muscle is one of the major components of the development of type 2 diabetes (T2D). Mitochondrial dysfunction involves in the accumulation of toxic reactive oxygen species (ROS) that leads to insulin resistance. The aim of this study was to verify the involvement of mitochondrial DNA damage at ROS generation in skeletal muscle during development of T2D. Wistar rats were fed a diet containing 60% fat over 8 weeks and at day 14 a single injection of STZ (25 mg/kg) was administered (T2D-induced). Control rats received standard food and an injection of citrate buffer. Blood and soleus muscle were collected. Abdominal fat was quantified as well as glucose, triglyceride, LDL, HDL, and total cholesterol in plasma and mtDNA copy number, cytochrome b (cytb) mRNA, 8-hydroxyguanosine, and 8-isoprostane (a marker of ROS) in soleus muscle. T2D-induced animal presented similar characteristics to humans that develop T2D such as changes in blood glucose, abdominal fat, LDL, HDL and cholesterol total. In soleus muscle 8-isoprostane, mtDNA copy number and 8-hydroxyguanosine were increased, while cytb mRNA was decreased in T2D. Our results suggest that in the development of T2D, when risks factors of T2D are present, intracellular oxidative stress increases in skeletal muscle and is associated with a decrease in cytb transcription. To overcome this process mtDNA increased but due to the proximity of ROS generation, mtDNA remains damaged by oxidation leading to an increase in ROS in a vicious cycle accounting to the development of insulin resistance and further T2D.

Seropositivity diagnosis for hantavirus in Jataí, Goiás State, Brazil.

INTRODUCTION:: Emerging diseases are of great interest, especially those associated with high mortality rates such as hantaviruses. We aimed to conduct a seroepidemiological survey to determine the levels of hantavirus infection. METHODS:: In-house enzyme-linked immunosorbent assay (ELISA) was used to detect specific antibodies. RESULTS:: Of the 429 samples collected, seropositivity of 3.9% to anti-hantavirus immunoglobulin G (IgG) was observed (CI 95%: 2.3-5.7). Moreover, in three cases, immunoglobulin M (IgM) was detected, of which two were diagnosed as hantavirus cardiopulmonary syndrome (HCPS). CONCLUSIONS:: Our data indicate the considerable occurrence of previous hantavirus infections, highlighting occurrences from sub-clinical cases to HCPS.

Seropositivity diagnosis for hantavirus in Jataí, Goiás State, Brazil

Abstract INTRODUCTION: Emerging diseases are of great interest, especially those associated with high mortality rates such as hantaviruses. We aimed to conduct a seroepidemiological survey to determine the levels of hantavirus infection. METHODS: In-house enzyme-linked immunosorbent assay (ELISA) was used to detect specific antibodies. RESULTS: Of the 429 samples collected, seropositivity of 3.9% to anti-hantavirus immunoglobulin G (IgG) was observed (CI 95%: 2.3-5.7). Moreover, in three cases, immunoglobulin M (IgM) was detected, of which two were diagnosed as hantavirus cardiopulmonary syndrome (HCPS). CONCLUSIONS: Our data indicate the considerable occurrence of previous hantavirus infections, highlighting occurrences from sub-clinical cases to HCPS.

Cross-sectional study on case fatality rate due to hantavirus infection in Goiás State, Brazil, 2007-2013. / Estudo transversal da letalidade da hantavirose no estado de Goiás, 2007-2013.

OBJECTIVE: to describe the epidemiological and clinical profile of hantavirus infection and to analyze factors associated with case-fatality in Goiás, Brazil. METHODS: this was a cross-sectional study on case fatality due to hantavirus infection from 2007 to 2013 using data from the Notifiable Diseases Information System (SINAN) for Goiás State. Logistic regression analysis was performed to estimate odds ratios (OR) with 95% confidence intervals (95%CI). RESULTS: 1,171 suspected cases were reported, of which 73 (6.2%) were confirmed. Among the confirmed cases, greater frequency was found among males (n=50), fever was the most common symptom (n=70), and there was a high proportion of hospitalization (n=68). The case-fatality rate was 57.5% . The following factors were associated with death: acute respiratory failure (ARF) (OR=3.6; 95%CI 1.2;10.6), hemoconcentration (OR=3.3; 95%CI 1.1;7.9) and not using a mechanical ventilator (OR=3.4; 95%CI 1.3;9.1). After adjustment, the ARF was still associated with death (OR=3.4; 95%CI 1.0;11.6). CONCLUSION: the case-fatality rate was high, primarily associated with respiratory failure.

Estudo transversal da letalidade da hantavirose no estado de Goiás, 2007-2013 / Estudio transversal de la letalidad de la infección por hantavirus en el estado de Goiás, Brasil, 2007-2013 / Cross-sectional study on case fatality rate due to hantavirus infection in Goiás State, Brazil, 2007-2013

OBJETIVO: descrever o perfil epidemiológico e clínico da hantavirose e analisar fatores associados à letalidade em Goiás, Brasil. MÉTODOS: foi conduzido um estudo transversal com dados do Sistema de Informação de Agravos de Notificação (Sinan), referentes ao período de 2007 a 2013, no estado de Goiás. Regressão logística foi empregada para estimar razões de chances (OR) com intervalos de confiança de 95% (IC95%). RESULTADOS: foram notificados 1.171 casos suspeitos de hantavirose e 73 (6,2%) confirmados. Entre os confirmados, observou-se maior frequência entre homens (n=50), febre como sintoma mais frequente (n=70) e elevada proporção de hospitalizações (n=68). A taxa de letalidade foi de 57,5%. Foram fatores associados ao óbito: insuficiência respiratória aguda (IRpA) (OR=3,6; IC95%1,2;10,6), hemoconcentração (OR=3,3; IC95%1,1;7,9) e não uso do respirador mecânico (OR=3,4; IC95%1,3;9,1). Após ajuste, a IRpA permaneceu associada ao óbito (OR=3,4; IC95%1,0;11,6). CONCLUSÃO: foi identificada alta taxa de letalidade, associada principalmente com insuficiência respiratória.

OBJETIVO: evaluar el perfil clínico y epidemiológico del hantavirus y los factores asociados con su letalidad en Goiás, Brasil. MÉTODOS: estudio transversal usando datos del Sistema de Información de Enfermedades de Declaración Obligatoria (Sinan), referentes al periodo 2007-2013, en el estado de Goias. Usamos regresión logística para calcular odds ratio (OR) con intervalos de confianza al 95%. RESULTADOS: fueron reportados 1.171 casos sospechosos de hantavirus 73 fueron confirmados (6,2%). Entre los confirmados la frecuencia fue mayor entre hombres (n=50), fiebre fue síntoma más común (n=70), 68 fueron hospitalizados, la tasa de letalidad fue 57,5%. Variables asociadas con letalidad: insuficiencia respiratoria aguda (IRpA) (OR=3,6 IC95% 1,2; 10,6), hemoconcentración (OR=3.3 IC95% 1,1; 7,9) y no usar respirador mecánico (OR=3,4 IC95% 1,3; 9,1). Sólo IRpA se mantuvo asociado en modelos multivariados (OR=3,4 IC95% 1,0; 11,6). CONCLUSIÓN: identificamos una alta tasa de letalidad asociada principalmente con insuficiencia respiratoria.

OBJECTIVE: to describe the epidemiological and clinical profile of hantavirus infection and to analyze factors associated with case-fatality in Goiás, Brazil. METHODS: this was a cross-sectional study on case fatality due to hantavirus infection from 2007 to 2013 using data from the Notifiable Diseases Information System (SINAN) for Goiás State. Logistic regression analysis was performed to estimate odds ratios (OR) with 95% confidence intervals (95%CI). RESULTS: 1,171 suspected cases were reported, of which 73 (6.2%) were confirmed. Among the confirmed cases, greater frequency was found among males (n=50), fever was the most common symptom (n=70), and there was a high proportion of hospitalization (n=68). The case-fatality rate was 57.5% . The following factors were associated with death: acute respiratory failure (ARF) (OR=3.6; 95%CI 1.2;10.6), hemoconcentration (OR=3.3; 95%CI 1.1;7.9) and not using a mechanical ventilator (OR=3.4; 95%CI 1.3;9.1). After adjustment, the ARF was still associated with death (OR=3.4; 95%CI 1.0;11.6). CONCLUSION: the case-fatality rate was high, primarily associated with respiratory failure.

Serological evidence of hantavirus infection in an urban area in Mato Grosso State, Brazil.

INTRODUCTION: In Brazil, Mato Grosso (MT) has the highest number of hantavirus cardiopulmonary syndrome cases. Our study aimed to identify anti-hantavirus antibodies in the sera of patients from Sinop, MT, presenting with acute febrile illness. METHODS: A retrospective analysis of data for 198 sera samples assessed using enzyme-linked immunosorbent assay (ELISA) was conducted. RESULTS: Immunoglobulins G (IgGs) against the hantavirus nucleoprotein were found in 13.6% of the tested sera. No sample had immunoglobulin M (IgM) antibodies to hantavirus. Seropositivity occurred mainly in female residents in urban areas who worked around the household. CONCLUSIONS: Our findings suggest circulation of hantavirus in Sinop.

Hantavirus cardiopulmonary syndrome: a report of two cases / Síndrome cardiopulmonar por hantavírus: relato de dois casos

Infection with hantavirus, from the family Bunyaviridae, causes hantavirus cardiopulmonary syndrome (HCPS) in the Americas. This highly lethal anthropozoonosis afflicts preferentially individuals in rural areas and is transmitted by aerosol of excreta from infected wild rodents. The aim of this study is to report the almost simultaneous occurrence of two cases of HCPS in the municipality of Jataí, state of Goiás, Brazil.

A infecção por hantavírus, família Bunyaviridae, provoca a síndrome cardiopulmonar por hantavírus (SCPH) nos países da América. Ela é uma antropozoonose, de elevada letalidade, que tem acometido preferencialmente indivíduos em contato com o meio rural, sendo transmitida por aerossóis a partir das excretas dos roedores silvestres infectados. O objetivo deste estudo foi relatar a ocorrência, quase que simultânea, de dois casos de SCPH ocorridos no município de Jataí, Estado de Goiás, Brasil.

Principais parâmetros biológicos avaliados em erros na fase pré-analítica de laboratórios clínicos: revisão sistemática / Main biological parameters evaluated in pre-analytical phase errors at clinical laboratories: a systematic review

O diagnóstico laboratorial passou por várias mudanças devido à automatização. Além do aparelhamento, a adoção de um programa de garantia de qualidade (PGQ) está resultando em maior precisão nos exames. Para fins de controle em qualidade, o processamento de uma amostra biológica é didaticamente dividido em três fases: pré-analítica, analítica e pós-analítica. Na fase pré-analítica ocorre a maioria dos erros; a divulgação dessas falhas e sua discussão corroboram para a eficiência dos PGQs. No presente estudo, descrevemos as principais variações biológicas encontradas na fase pré-analítica em laboratórios clínicos, por meio de uma revisão sistemática. Fizeram parte dessa revisão 14 artigos. Os parâmetros biológicos descritos na revisão foram, principalmente, glicose, colesterol, triglicérides, enzimas e hormônios. Um erro frequente na punção venosa foi o uso prolongado do torniquete e entre as principais causas de erros observadas foram tempo de armazenamento, tempo de torniquete, técnicas de flebotomia, falta de informações aos pacientes, relação incorreta sangue/anticoagulante, tubos inadequados, amostras contaminadas, medicamentos e alterações interlaboratoriais. Nossos achados são similares aos encontrados em outras pesquisas, mas não encontramos estudos que avaliassem especificamente as alterações na fase pré-analítica decorrentes do uso de medicamentos. Concluímos que os parâmetros biológicos mais avaliados coincidiram com os exames de rotina e uma das formas de evitar às inexatidões laboratoriais é pôr em prática um eficiente PGQ e a produção de trabalhos que explanem o assunto a pacientes e profissionais da saúde.

Laboratory diagnosis has undergone several changes due to automation. Both equipment supplying and the introduction of quality assurance programs (QAP) have led to higher precision in tests. With the aim to promote quality control, the processing of biological samples comprises three phases: pre-analytical, analytical and post-analytical. Most errors occur in the pre-analytical phase. Thus, their determination and corresponding assessment maximize QAP efficiency. In this study, by means of a systematic review, which comprised 14 articles, we describe the main biological variations found in the pre-analytical phase at clinical laboratories. The biological parameters described in the review included glucose, cholesterol, triglycerides, enzymes and hormones. As far as venipuncture is concerned, a common error was the prolonged use of tourniquet. The main error causes were the following: storage time, tourniquet time, phlebotomy techniques, insufficient information to patients, incorrect blood/anticoagulant ratio, inadequate tubes, contaminated samples, medication and interlaboratory alterations. Our results corroborated other studies, although we did not find other investigations that specifically evaluated changes in the pre-analytical phase due to the use of medication. The most assessed biological parameters coincided with clinical tests. Accordingly, both the implementation of an efficient QAP and the development of professional awareness may prevent laboratory inaccuracies.