ABSTRACT
Resumen La troponina cardiaca es el marcador bioquímico más sensible y específico de daño/necrosis miocárdica, de ahí que desempeñe un papel crucial en el diagnóstico del síndrome coronario agudo. Sin embargo, en ocasiones, como en el caso clínico que se describirá, la elevación anormal de troponina no siempre obedece a un síndrome coronario agudo trombótico, sino a causa cardiaca sin enfermedad coronaria significativa, causa extracardiaca o alteración analítica (verdaderos falsos positivos). El interés de este caso radica en que siempre debería tenerse en mente la posibilidad de que se produzca un falso positivo de troponina por causa analítica, en especial en situaciones clínicas sin una razón obvia de daño miocárdico y cuando no sea evidente la confirmación de daño miocárdico mediante pruebas complementarias.
Abstract Cardiac troponin is the most sensitive and specific biochemical marker for myocardial damage / necrosis, and thus has a crucial role in the diagnosis of acute coronary syndrome. However, occasionally, as in the clinical case that will be described, the abnormal elevation of troponin does not always obey that of an acute coronary syndrome, but also to a cardiac cause with no significant coronary disease, extra-cardiac cause, or analytical change (true false positives). The interest in this case lies in that it should always be borne in mind that a false positive troponin can be produced due to an analytical cause. This can be the case in clinical situations with no obvious reason for myocardial damage and when the confirmation of myocardial damage may not be evident using complementary tests.
Subject(s)
Humans , Male , Middle Aged , Troponin I , False Positive Reactions , Lifting , Coronary Disease , Acute Coronary SyndromeABSTRACT
<b>Objective: </b>Several drugs can cause analytical interference in clinical laboratory tests. To prevent errors in clinical judgment as a result of false data, we investigated the information available on the interference of ethical drugs in these tests.<br><b>Methods: </b>We examined the information available by collecting and evaluating information in package insert leaflets, collecting and evaluating clinical data on three drugs (bucillamin, captopril, and epalrestat) which affect clinical laboratory test results, and conducting a questionnaire survey of healthcare workers.<br><b>Results: </b>From the information available on package inserts, 227 drugs were identified as having the potential to interfere with the chemical reactions used in clinical laboratory tests. However, the insert information is not sufficient for use in clinical settings because the frequency rate and causative factors of interference are not stated clearly. The clinical survey results reveal that 40% of patients taking bucillamine and 20% of patients taking epalrestat tested false-positive for urinary ketones. According to the questionnaire results, medical technologists were more interested than pharmacists and physicians in how drugs affect clinical laboratory tests.<br><b>Conclusion: </b>The information currently available on the interference of drugs in clinical laboratory tests is problematical, and it is therefore necessary to collect more clinical data for the proper interpretation and evaluation of abnormal laboratory values.
ABSTRACT
A determinação da concentração circulante de hormônios por meio de imunoensaios deu início à era moderna da Endocrinologia e, desde então, esses ensaios vêm sendo aprimorados em praticamente todos os seus aspectos. Os imunoensaios são classificados como competitivos ou não competitivos. Nos métodos competitivos, o hormônio endógeno compete com um hormônio marcado pela ligação a quantidades limitadas de anticorpos específicos. Nos imunoensaios não competitivos, são utilizados pares de anticorpos complementares para capturar e detectar o hormônio de interesse. Esses ensaios são também conhecidos como ensaios sanduíche e denominados de acordo com o sistema de detecção que utilizam. Diante do aprimoramento contínuo das técnicas de imunoensaio, é importante ressaltar que o clínico não deve considerar seu resultado como evidência de diagnóstico definitivo, mas como ferramenta para auxiliar a confirmação ou excluir uma impressão clínica.
The description of immunoassays for measurement of circulating concentrations of hormones initiated the modern endocrine era. Since its initial description, immunoassay methodology has been continuously improved. Immunoassay techniques are described as either competitive or noncompetitive assays. In competitive methods the endogenous hormone competes with radiolabeled hormone for binding with limited amount of specific antibodies. Noncompetitive immunoassays use complementary pairs of antibodies to capture and detect the hormone of interest. These assays are also known as sandwich methods and are named based on the detection method used. As immunoassay techniques continues to advance it must be emphasized that clinicians should not consider their results as evidence of a definite diagnosis, but as a tool to confirm or refute a clinical impression.