Analytical Performance of COVID-19 Detection Methods (RT-PCR): Scientific and Societal Concerns.

Background. Health and social management of the SARS-CoV-2 epidemic, responsible for the COVID-19 disease, requires both screening tools and diagnostic procedures. Reliable screening tests aim at identifying (truely) infectious individuals that can spread the viral infection and therefore are essential for tracing and harnessing the epidemic diffusion. Instead, diagnostic tests should supplement clinical and radiological findings, thus helping in establishing the diagnosis. Several analytical assays, mostly using RT-PCR-based technologies, have become commercially available for healthcare workers and clinical laboratories. However, such tests showed some critical limitations, given that a relevant number of both false-positive and false-negative cases have been so far reported. Moreover, those analytical techniques demonstrated to be significantly influenced by pre-analytical biases, while the sensitivity showed a dramatic time dependency. Aim. Herein, we critically investigate limits and perspectives of currently available RT-PCR techniques, especially when referring to the required performances in providing reliable epidemiological and clinical information. Key Concepts. Current data cast doubt on the use of RT-PCR swabs as a screening procedure for tracing the evolution of the current SARS-COV-2 pandemic. Indeed, the huge number of both false-positive and false-negative results deprives the trustworthiness of decision making based on those data. Therefore, we should refine current available analytical tests to quickly identify individuals able to really transmit the virus, with the aim to control and prevent large outbreaks.

Evaluation of PSA requests in men under 40 years of age / Avaliação das solicitações de PSA em homens com menos de 40 anos de idade

ABSTRACT Objectives: To evaluate the frequency of PSA requests in men under age 40 years; and to observe the possible influence of medical specialty of the requesting physician. Material and method: This is an observational, cross-sectional study using the database of a national clinical laboratory on PSA requests from October 1, 1997 until December 31, 2016. Descriptive statistics were used. The work was approved by the Ethics Committee of our institution. Results: 2,514,375 PSA requests were evaluated, 158,399 (6.3%) in men younger than 40 years old. These percentages did not vary significantly when observed over time (1998-2016). The prevalence of requests for patients under 40 years of age, was 18.2% among general practitioners; 16.5% among cardiologists, 8.4% among geriatricians and 6.8% among urologists. Conclusion: There is a very high frequency of PSA requests in men with low probability of benefiting from the test. It is necessary to invest in the dissemination of best practices related to prostate cancer screening, especially among clinicians and cardiologists.

RESUMEN Objetivos: Evaluar la cantidad de solicitudes del antígeno prostático específico (PSA) para hombres menores de 40 años, así como observar la posible influencia de la especialidad del médico solicitante. Material y método: Estudio observacional, de corte transversal, que utilizó la base de datos de un gran laboratorio clínico brasileño con las solicitudes de PSA desde el 1 de octubre de 1997 hasta el 31 de Diciembre de 2016. Se analizaron los datos mediante estadística descriptiva. El estudio fue aprobado por el comité ético de nuestra institución. Resultados: Se evaluaron 2.514.375 solicitudes de PSA, 158.399 (6.3%) en hombres menores de 40 años. Los porcentajes no variaron significantemente con el tiempo (1998-2016). La prevalência de solicitudes para pacientes menores de 40 años, fue de 18,2% entre los clínicos, 16,5% entre cardiólogos, 8,4% geriatras y 6,8% entre los urólogos. Conclusión: Hay una cantidad muy grande de solicitudes de PSA en hombres con baja probabilidad de sacar provecho de la realización del test. Es necesario invertir en la divulgación de mejores prácticas de tamizaje del cáncer de próstata, especialmente entre los clínicos y cardiólogos.

RESUMO Objetivos: Avaliar a frequência das solicitações de antígeno prostático específico (PSA) para homens com menos de 40 anos, bem como observar a possível influência da especialidade do médico solicitante. Material e método: Estudo observacional, de corte transversal, que utilizou o banco de dados de um laboratório clínico brasileiro de grande porte com as solicitações de PSA no período de 1º de outubro de 1997 a 31 de dezembro de 2016. Os dados foram analisados por estatística descritiva. O trabalho foi aprovado pelo Comitê de Ética de nossa instituição. Resultados: Foram avaliadas 2.514.375 solicitações de PSA, 158.399 (6,3%) em homens com menos de 40 anos. Esses percentuais não variaram significativamente quando observados no tempo (1998-2016). Entre as solicitações com identificação da especialidade do médico para pacientes com menos de 40 anos de idade, 18,2% foram de clínicos, 16,5% de cardiologistas, 8,4% de geriatras e 6,8% de urologistas. Conclusão: Há uma frequência muito elevada de solicitações de PSA em homens com baixa probabilidade de se beneficiarem com a realização do exame. Faz-se necessário investimento na divulgação das melhores práticas em relação ao rastreamento do câncer de próstata, especialmente entre os clínicos e cardiologistas.

Improving serum calcium test ordering according to a decision algorithm.

AIM: To detect differences in the pattern of serum calcium tests ordering before and after the implementation of a decision algorithm. METHODS: We studied patients admitted to an internal medicine ward of a university hospital on April 2013 and April 2016. Patients were classified as critical or non-critical on the day when each test was performed. Adequacy of ordering was defined according to adherence to a decision algorithm implemented in 2014. RESULTS: Total and ionised calcium tests per patient-day of hospitalisation significantly decreased after the algorithm implementation; and duplication of tests (total and ionised calcium measured in the same blood sample) was reduced by 49%. Overall adequacy of ionised calcium determinations increased by 23% (P=0.0001) due to the increase in the adequacy of ionised calcium ordering in non-critical conditions. CONCLUSIONS: A decision algorithm can be a useful educational tool to improve adequacy of the process of ordering serum calcium tests.

Clinical Applications of Point-of-Care Testing in Different Conditions.

BACKGROUND: The use of point-of-care testing (POCT) in different clinical applications is justified by the fact that the time to release the result is shortened, allowing the physician to define the diagnosis and most appropriate therapy in a shorter time. However, the negative aspects must also be highlighted and studied so that we can move forward with the use of these devices. These negative aspects include greater analytical imprecision compared to laboratory automation, the variability between different equipment from different manufacturers, the risk of inappropriate use, a low level of global regulation, higher costs compared with laboratory testing and cost ineffectiveness in terms of health care. Methods and. RESULTS: This review presents some clinical applications of POCT in different scenarios, such as for diabetes mellitus, infectious diseases, pediatrics, and chronic kidney disease, among others. CONCLUSIONS: We hope to see a global consensus on an acceptable quality standard for performing POCT that is adaptable, practical, and cost effective in primary care settings, ensuring patient safety, and minimizing the risk of harm.

Point-of-Care Testing: General Aspects.

Point-of-Care Testing (POCT) has been highlighted in the health care sector in recent decades. On the other hand, due to its low demand, POCT is at a disadvantage compared to conventional equipment, since its cost is inversely proportional to the volume of use. In addition, for the implementation of POCT to succeed, it is essential to rely on the work of a multidisciplinary team. The awareness of health professionals of the importance of each step is perhaps the critical success factor. The trend towards the continuous advancement of the use of POCT and the great potential of its contributions reinforce the need to implement quality management tools, including performance indicators, to ensure their results. This review presents some advantages and disadvantages concerning POCT and the real need to use it. A worldwide call for the availability of easy-to-use health technologies that are increasingly closer to the final user is one of the main reasons for this focus.

The measurement of serum osmolality and its application to clinical practice and laboratory: literature review / A medida da osmolalidade sérica e sua aplicação na prática clínica e laboratorial: revisão da literatura

ABSTRACT Introduction: Serum osmolality is an essential laboratory parameter to understand several clinical disorders such as electrolyte disturbances, exogenous intoxication and hydration status. Objective: This study aims to update knowledge about the osmolality examination through research papers published to date. Materials and methods: The survey was conducted on PubMed database. It highlights main concepts, both historical and physiological aspects, and the clinical applications of the serum osmolality test. In addition, an extensive survey of formulas for the serum osmolality calculation was conducted. Discussion: The measurement of serum osmolality is relevant in changes in intracellular and extracellular balance, as a trusted and valuable indicator of solute concentration in the blood. The mathematical equations for serum osmolality calculation acquire relevance in health services where serum is not available, and situations in which calculation of the osmolal gap is necessary, but the variability of the formulas is a significant bias. Conclusion: The measurement of serum osmolality is useful in cases of dehydration, sodium and potassium disorders, glucose alteration, exogenous poisoning, adrenal insufficiency, neurological injury, physical exercise and others.

RESUMO Introdução: A osmolalidade sérica constitui um parâmetro laboratorial importante para compreensão de diversas desordens clínicas, como os distúrbios eletrolíticos, as intoxicações exógenas e o status de hidratação. Objetivo: Este trabalho visa atualizar os conhecimentos acerca do exame de osmolalidade por meio da pesquisa de artigos científicos publicados até a presente data. Materiais e métodos: A pesquisa foi realizada no banco de dados do PubMed. Este artigo de atualização aborda os principais conceitos, aspectos históricos, aspectos fisiológicos e aplicações clínicas do exame de osmolalidade sérica. Foi também realizado um levantamento das diferentes fórmulas propostas para o cálculo da osmolalidade sérica. Discussão: A medida da osmolalidade sérica é pertinente nas alterações do equilíbrio intra e extracelular, sendo um bom indicador para avaliar as concentrações de solutos no sangue. As fórmulas matemáticas para o cálculo da osmolalidade sérica são úteis quando a medida laboratorial não está disponível, bem como nas situações em que o cálculo do gap osmolal se faz necessário, mas a variabilidade das fórmulas é um viés significativo. Conclusão: A medida da osmolalidade sérica é útil na avaliação de diversas condições clínicas, como na desidratação, nos distúrbios dos íons sódio e potássio, nas disglicemias, nas intoxicações exógenas, na insuficiência adrenal, nas lesões neurológicas, nos exercícios físicos, entre outras.

Laboratory Tests Ordering Pattern by Medical Residents From a Brazilian University Hospital.

OBJECTIVES: The adequacy of laboratory test orders by medical residents is a longstanding issue. The aim of this study is to analyze the number, types, and pattern of repetition of tests ordered by medical residents. METHODS: We studied all tests ordered over a 1-year period for inpatients of an internal medicine ward in a university hospital. Types, results, and repetition pattern of tests were analyzed in relation to patients' diagnoses. RESULTS: We evaluated 117,666 tests, requested for 1,024 inpatients. The mean number of tests was 9.5 per day. The test repetition pattern was similar, regardless of patients' diagnoses, previous test results, or duration of stay. The probability of an abnormal result after a sequence of three normal tests was lower than 25%, regardless of the diagnosis. CONCLUSIONS: Number of tests and repetition were both high, imposing costs, discomfort, and risks to patients, thus warranting further investigation.

The critical value concept in clinical laboratory / O conceito de valores críticos no laboratório clínico

ABSTRACT The critical value is a laboratory result representing a pathophysiological state that offers risk to a patient's life. The communication of these results is a laboratory responsibility and, according to the literature, 95% of physicians consider it useful in decision-making and patient management. Two-thirds of critical results lead to some change in therapeutic approach. The communication of critical results is a requirement for laboratory accreditation programs. Thus laboratories should establish a list of tests, their critical values, and the procedure describing the communication flow. The performance indicator for this activity should consider the time between results release and their effective communication, and the percentage of successful communication. There is no standardization of laboratory parameters that need to have critical values established, not even the ranges to be considered for notification purposes. The frequent update of test lists and critical value ranges based on literature reviews and on experience exchange among clinical laboratories ensure the continuous improvement process for this procedure and patient safety.

RESUMO O valor crítico é um resultado laboratorial que representa um estado fisiopatológico de risco à vida do paciente. A comunicação desses resultados é de responsabilidade do laboratório e, segundo a literatura, 95% dos médicos a considera útil na adoção de condutas e no manuseio dos pacientes. Dois terços dos resultados críticos resultam em alguma mudança na conduta terapêutica. A comunicação dos resultados críticos é um procedimento previsto nas listas de verificação dos programas de acreditação laboratorial, portanto o laboratório deve estabelecer a lista dos exames, os respectivos valores críticos e o procedimento, descrevendo o fluxo de comunicação. O indicador de desempenho para esta atividade deve considerar o tempo decorrido entre a liberação do resultado e a sua efetiva comunicação e o percentual de sucesso na comunicação. Não existe padronização acerca dos parâmetros laboratoriais que necessitam ter valores críticos estabelecidos, nem mesmo os intervalos a serem considerados para fins de notificação. A atualização frequente da lista de exames e dos intervalos de valores críticos com base na revisão da literatura e na troca de experiências entre os laboratórios clínicos garante o processo de melhoria contínua para esse procedimento e a segurança do paciente.

Validation protocol for multiple blood gas analyzers in accordance with laboratory accreditation programs / Protocolo de validação de múltiplos equipamentos para análise de gases sanguíneos em conformidade com os programas de acreditação laboratorial

ABSTRACTIntroduction:The results of blood gas analysis using different instrumentation can vary widely due to the methodological differences, the calibration procedures and the use of different configurations for each type of instrument.Objective:The objective of this study was to evaluate multiple analytical systems for measurement of blood gases, electrolytes and metabolites in accordance with the accreditation program (PALC) of Sociedade Brasileira de Patologia Clínica/Medicina Laboratorial (SBPC/ML).Materials and methods:20 samples were evaluated in three ABL800 Flex (Radiometer Medical ApS, Denmark) blood gas analyzers, and the results were compared with those of the device in use, which was considered the reference. The analysis of variance (Anova) was applied for statistical purposes, as well as the calculation of mean, standard deviation and coefficient of variation.Results:The p values obtained in the statistical analysis were: pH = 0.983, pO2 = 0.991, pCO2 = 0.353, lactate = 0.584, glucose = 0.995, ionized calcium = 0.983, sodium = 0.991, potassium = 0.926, chlorine = 0.029.Conclusion:The evaluation of multiple analytical systems is an essential procedure in the clinical laboratory for quality assurance and accuracy of the results.

RESUMOIntrodução:Os resultados da análise dos gases sanguíneos utilizando diferentes equipamentos podem apresentar grandes variações decorrentes das diferenças metodológicas, dos procedimentos de calibração e da aplicação de configurações distintas para cada tipo de instrumento.Objetivo:O objetivo deste trabalho foi avaliar múltiplos sistemas analíticos para teste de gases sanguíneos, eletrólitos e metabólitos, em conformidade com o Programa de Acreditação de Laboratórios Clínicos (PALC) da Sociedade Brasileira de Patologia Clínica/Medicina Laboratorial (SBPC/ML).Materiais e métodos:Foram avaliadas 20 amostras em três analisadores de gases sanguíneos ABL800 Flex (Radiometer Medical ApS, Dinamarca) em relação ao equipamento em uso, que foi considerado referência. A análise de variância (Anova) foi aplicada para fins de estudo estatístico dos resultados obtidos nos quatro equipamentos, bem como o cálculo da média, do desvio padrão e do coeficiente de variação.Resultados:Os valores de p obtidos na análise estatística foram: pH = 0,983, pO2 = 0,991, pCO2 = 0,353, lactato = 0,584, glicose = 0,995, cálcio ionizado = 0,983, sódio = 0,991, potássio = 0,926 e cloro = 0,029.Conclusão:A avaliação de múltiplos sistemas analíticos é procedimento essencial no laboratório clínico para garantia da qualidade e da exatidão dos resultados.

Vitamin D: non-skeletal actions and rational use.

Recent years have witnessed a substantial increase in the number of seric determinations of vitamin D, in a worldwide basis. At Hospital das Clínicas of Faculdade de Medicina of Universidade de São Paulo that increase reached 700% over the last four years. Nevertheless there are many controversies on the literature about the role of vitamin D in conditions unrelated to the musculoskeletal system. In this study the metabolism, sources and actions of vitamin D on the body are reviewed. Observational studies, clinical trials, systematic reviews and metanalysis which focused on the relationship between the vitamin and conditions such as cancer, cardiovascular disease, diabetes and falls were searched on the literature, analyzed and discussed. Results are presented as quiz and answer, tables and a figure. The role of vitamin D on the above-mentioned conditions is discussed, and the controversial issues stressed.

Vitamina D: ações extraósseas e uso racional / Vitamin D: non-skeletal actions and rational use

O número de dosagens do nível sérico de vitamina D tem apresentado crescimento muito expressivo nos últimos anos em todo o mundo. No Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo houve aumento de cerca de 700% em quatro anos nas solicitações desse hormônio. No entanto, há controvérsias na literatura sobre a real utilidade de sua dosagem e/ou suplementação, exceto em situações diretamente relacionadas ao metabolismo ósseo. No presente trabalho são revistos o metabolismo, as fontes e as ações da vitamina D no organismo. Estudos observacionais, ensaios clínicos, revisões sistemáticas e metanálises, cujo foco é a relação entre vitamina D e doenças ou condições clínicas, como câncer, doenças cardiovasculares, diabetes e quedas, foram pesquisados na literatura, analisados e discutidos. Os resultados estão apresentados em forma de perguntas e respostas, tabelas e figura. Discute-se o papel da vitamina D em todas essas situações, e salientam-se os pontos controvertidos.

Recent years have witnessed a substantial increase in the number of seric determinations of vitamin D, in aworldwide basis. At Hospital das Clínicas of Faculdade de Medicina of Universidade de São Paulo that increase reached 700% over the last four years. Nevertheless there are many controversies on the literature about the role of vitamin D in conditions unrelated to themusculoskeletal system. In this study the metabolism, sources and actions of vitamin D on the body are reviewed. Observational studies, clinical trials, systematic reviews and metanalysis which focused on the relationship between the vitamin and conditions such as cancer, cardiovascular disease, diabetes and falls were searched on the literature, analyzed and discussed. Results are presented as quiz and answer, tables and a figure. The role of vitamin D on the above-mentioned conditions is discussed, and the controversial issues stressed.

C-reactive protein: clinical applications and proposals for a rational use.

C-reactive protein (CRP) is an acute-phase protein whose requests have been growing exponentially in several countries, including Brazil. In this study, the use of CRP in several clinical situations was reviewed by a group of physicians comprised by specialists in internal medicine, medical emergencies, intensive care, screening, and laboratory medicine, aiming to analyze the applicable literature and to propose guidelines for a more rational use of this laboratory test. The result was the creation of flowcharts guiding CRP request, adjusted to four different healthcare environments, namely, intensive care units, emergency room, wards, and outpatient clinics. These flowcharts, as well as a more detailed discussion on several clinical recommendations for the test, are presented in this study.

Proteína C reativa: aplicações clínicas e propostas para utilização racional / C-reactive protein: clinical applications and proposals for a rational use

A proteína C reativa (PCR) é uma das proteínas de fase aguda cuja solicitação tem crescido de forma exponencial em vários países, incluindo o Brasil. Neste estudo, a utilidade da PCR em diversas situações clínicas foi revisada por um grupo de médicos composto por especialistas em Medicina Interna, Emergências Médicas, Terapia Intensiva, Rastreamento e Medicina Laboratorial com o objetivo de analisar a literatura pertinente e propor diretrizes para o uso mais racional desse exame laboratorial. O resultado foi a criação de fluxogramas orientadores da solicitação de PCR adaptados a quatro ambientes assistenciais diferentes, sendo eles unidades de terapia intensiva, pronto-socorro, enfermarias e ambulatórios. Esses fluxogramas e uma discussão mais detalhada sobre as diversas indicações clínicas do exame são apresentados neste estudo.

C-reactive protein (CRP) is an acute-phase protein whose requests have been growing exponentially in several countries, including Brazil. In this study, the use of CRP in several clinical situations was reviewed by a group of physicians comprised by specialists in internal medicine, medical emergencies, intensive care, screening, and laboratory medicine, aiming to analyze the applicable literature and to propose guidelines for a more rational use of this laboratory test. The result was the creation of flowcharts guiding CRP request, adjusted to four different healthcare environments, namely, intensive care units, emergency room, wards, and outpatient clinics. These flowcharts, as well as a more detailed discussion on several clinical recommendations for the test, are presented in this study.

Diminished mycophenolic acid exposure caused by omeprazole may be clinically relevant in the first week posttransplantation.

BACKGROUND: Some studies have reported a decreased absorption of mycophenolic acid (MPA) from mycophenolate mofetil (MMF) in renal transplanted (RTx) patients under proton-pump inhibitors (PPIs). There is still a lack of information regarding (1) whether this effect occurs when MMF is administered with either tacrolimus or cyclosporine A [calcineurin inhibitors (CNIs)], (2) whether the effect has the same amplitude during the first year after RTx, and finally (3) whether this decrease in exposure is clinically relevant. METHODS: We retrospectively analyzed the omeprazole effect in 348 12-hour pharmacokinetic samplings [area under the curve (AUC)(0-12h)] performed on days 7, 14, 30, 60, 180, and 360 after RTx in 77 patients who participated in previous trials. RESULTS: For all periods, the groups with and without PPI did not differ in all variables. By mixed-model analysis of variance, PPI reduced the MPA AUC(0-12h) (P < 0.0008) in the patients under both CNIs mainly due to decreased absorption (P = 0.049). In the tacrolimus group, a lower exposure seemed also due to a decreased MPA reabsorption at 10-12 hours. The PPI effect remains throughout the first year but was clinically more important on day 7. By Cox analysis, the use of PPI was associated with a 25% less chance of being adequately exposed to MPA (95% confidence interval 0.58-0.99, P = 0.04). Similarly, the number of patients underexposed to MPA (AUC < 30 ng·h/mL) was higher at most periods in the PPI group but again not statistically significant. CONCLUSIONS: These data indicate that PPI decreases the MPA exposure when associated with both CNIs but particularly in the first week after RTx. In this period, the MMF dose should be increased. This effect lasts throughout the first year but does not seem to be clinically relevant after the first week.

New ways to deal with known preanalytical issues: use of transilluminator instead of tourniquet for easing vein access and eliminating stasis on clinical biochemistry.

INTRODUCTION: Tourniquet due venous stasis can alter both concentration and/or activity of several blood analytes, but is rarely regarded as an issue of laboratory variability. To overcome the problem transillumination devices (TD) have been proposed for a stasis-free phlebotomy. In this paper the use of a TD in place of tourniquet during blood collection has been evaluated. MATERIALS AND METHODS: Blood was collected from 250 volunteers divided in five homogenous groups of tourniquet times (G1: 30 sec, G2: 60 sec, G3: 90 sec, G4:120 sec, G5: 180 sec) and compared to blood obtained using TD. All samples were analyzed for glucose (GLU), total protein (TP), albumin (ALB), triglycerides (TRIG), potassium (K), sodium (NA), phosphate (PHOS), calcium (CA), alkaline phosphatase (ALKP) and magnesium (MG). RESULTS: In respect of TD, G1 did not show statistically significant increases in all clinical chemistry tests; G2 showed increases for GLU, TP, ALB, TRIG, K, CA, MG and ALKP. G3 and G4, showed no significant increase only for PHOS. G5 showed significant increases in all the tests evaluated. Moreover, clinically significant variations were observed for TP, ALB, K and CA in G2 to G5; for NA in G3 to G5; for MG in G4 and G5; for GLU, TRIG, ALKP only in G5. CONCLUSIONS: These results support the application of TD in blood collection for routine clinical chemistry laboratory tests, suggesting its use should be more diffused.

The need of mycophenolic acid monitoring in long-term renal transplants.

BACKGROUND: There is little information regarding the 12-h mycophenolic acid (MPA) pharmacokinetics (PK), a way to monitor the drug and the need of frequent monitoring, in stable patients. METHODS: A cohort of 35 adults, under long-term mycophenolate mofetil (MMF) therapy plus cyclosporin A (n = 12), TACimus (n = 12) or MMF only (n = 11); all with prednisone had a 12-h MPA-PK performed to ascertain the percentage of them within a defined therapeutic window. In 13 other patients, two PK studies undergone 1 wk apart were performed to evaluate the need for frequent measurements. RESULTS: Fourteen (40%) patients were within the defined therapeutic window (36-60 microg h/mL). Nine patients (26%) were overexposed while 12 (34%) were underexposed. A Cmax> or =10 microg/mL was seen in 20 (57%) of the patients. These percentages were equally distributed between the treatment groups both for AUC0-12 and Cmax. The equations using C0, C2 or both predict exposure, although the use of C2 seems to be more adequate in clinical practice. There were no differences in MPA exposure in patients with a repeated PK evaluated 1 wk later. CONCLUSION: The use of MMF without monitoring MPA blood levels may cause over-/underexposure to the drug in stable recipients. However, in patients under MMF for more than 1 yr, MPA levels are stable and there is no need for frequent measurements.

Determinação da ferritina sérica por dois métodos imunológicos automatizados / Ferritin determination performed by two immunologic automated methods

A concentração de ferritina sérica está diretamente relacionada às reservas de ferro do organismo. A proposta de nosso trabalho foi comparar os resultados obtidos na determinação da ferritina sérica por dois métodos imunológicos automatizados, uma vez que os resultados obtidos podem implicar ou não em condutas terapêuticas. Foram analisadas 206 amostras de soro por nefelometria usando o kit N-Látex-Ferritin da Behring e por enzimaimunoensaio em micropartículas usando o kit IMx Abbott. O coeficiente de correlação entre os dois métodos foi de r² = 0,94. No entanto, quando o método de enzimaimunoensaio foi utilizado, a média dos resultados obtidos foi significativamente mais altos que a média dos resultados do método de nefelometria (p < 0,001). A seguinte equação de regressão foi obtida: y = 0,83x + 1,172, onde y é o resultado da nefelometria e x é o resultado do método IMx Abbott. A despeito da alta correlação obtida, os resultados confirmam a importância de se especificar a metodologia aplicada nos resultados reportados