Guía de Práctica Clínica para el diagnóstico de la amiloidosis: Parte 1/3. Año 2020

METHOD: Use the PICO format to generate a series of questions, focusing on the specificity and sensitivity of the amyloidosis diagnostic test. PubMed searches were conducted in English and Spanish from July to August 2019. The level of evidence and recommendation are based on the GRADE system (http://www.gradeworkinggroup.org/index.htm). The recommendations are graded according to their direction (for or against) and strength (strong and weak). Finally, it is recommended to use GLIA tools to evaluate the obstacles and facilitators in implementation. SUGGESTED EXPLANATION: A strong suggestion indicates a high degree of trust in support or opposition to the intervention. When defining a strong recommendation, this guide uses the "recommended" language. The weaker recommendations indicate that the outcome of the intervention (favorable or unfavorable) is doubtful. In this case, if a weak recommendation is defined, the "recommendation" language is used. HOW TO USE THESE GUIDELINES: Recommendations must be explained within the scope of special care in validated diagnostic studies conducted by specially trained doctors. Presumably, the attending physician has a high degree of suspicion of amyloidosis. It assumes that diagnostic research is conducted by well-trained doctors using a validated standardized method. This guide is intended for health care professionals and those involved in health care policies to help ensure that the necessary agreements have been reached to provide appropriate care. RECOMMENDATIONS: For patients with suspected amyloidosis, it is recommended: -Confirmation in the tissue by biopsy and Congo red staining with the characteristic green birefringence under polarized light is recommended. -Confirmation by electron microscopy of the biopsy tissue is recommended. -Protein typing by mass spectrometry is recommended. -Protein typing by optical and / or electronic immunomicroscopy is recommended, as long as there are reliable antibodies. -Measurement of serum free light chains is recommended for evaluation of a monoclonal plasma cell proliferative disorder. -Serum and urinary immunofixation is recommended for evaluation of a monoclonal plasma cell proliferative disorder. -Measurement of serum free light chains, plus serum and urinary immunofixation is recommended for the evaluation of a monoclonal plasma cell proliferative disorder. For patients suspected of having amyloidosis, it is suggested: -Demonstration of a monoclonal plasma cell proliferative disorder by demonstration of clonal plasma cells by the most sensitive technique available in the bone marrow for the diagnosis of AL-type amyloidosis. -Confirmation of ATTRv amyloidosis by DNA sequencing of the 4-exon amyloidogenic TTR gene in patients with suspected ATTRv amyloidosis.