RESUMO
There is a pressing need for more precise biomarkers of chronic kidney disease (CKD). Plasma samples from 820 subjects [231 with CKD, 325 with end-stage kidney disease (ESKD) and 264 controls] were analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) to determine a metabolic profile of 28 amino acids (AAs) and biogenic amines to test their value as markers of CKD risk and progression. The kynurenine/tryptophan ratio showed the strongest correlation with estimated glomerular filtration rate values (coefficient = -0.731, p < 0.0001). Models created with orthogonal partial least squares-discriminant analysis (OPLS-DA) containing the metabolic signature showed a high goodness of fit and predictability for controls/CKD (R2X:0.73:R2Y:0.92:Q2:0.92, p < 0.0001) and lower values for CKD/ESKD (R2X:0.56:R2Y:0.59:Q2:0.55, p < 0.0001). Based on generated VIP scores, the most relevant markers for segregating samples into control/CKD and CKD/ESKD groups were citrulline (1.63) and tryptophan (1.47), respectively. ROC analysis showed that the addition of the metabolic profile to a model including CKD classic risk factors improved the AUC from 86.7% (83.6-89.9) to 100% (100-100) for CKD risk (p < 0.0001) and from 63.0% (58.2-67.8) to 96.5% (95.3-97.8) for the risk of progression from CKD to ESKD (p < 0.0001). Plasma concentrations of AAs and related amines may be useful as diagnostic biomarkers of kidney disease, both for CKD risk and for progression of CKD patients to ESKD.
RESUMO
El CA 19-9 es uno de los marcadores tumorales (MT) más inespecíficos. El incremento de este marcador puede estar influido por diversas circunstancias, por lo que un resultado elevado debe ser interpretado siempre considerando el contexto clínico. Se presenta el caso clínico de un varón de 79 años con síntomas digestivos inespecíficos y con una elevación de CA 19-9 sin ninguna otra prueba complementaria con valores alterados, por lo que desde el laboratorio se realizó un estudio de interferencias para determinar la verosimilitud de este resultado. El objetivo de este trabajo es resaltar el papel que desempeña el laboratorio clínico en la interpretación de los MT en el diagnóstico del cáncer (AU)
CA 19-9 is one of the most non-specific tumour markers (TM). It may be increased in different conditions, and thus a high result must be interpreted in a clinical context. In this article the case is presented of a 79 year-old man who had non-specific gastrointestinal symptoms and an elevation of CA 19-9, with no other alterations in the complementary tests. Because of this, the laboratory carried out a complete interference study. The objective of the present work is to emphasise the role of the clinical laboratory in the interpretation of the TM in cancer diagnosis (AU)