RESUMO
MAIN PROBLEM: Luminex panel and single antigen beads (SAB) are used for screening and DSA specificity determination respectively. The cost of SAB may limit its general use, so some labs perform SAB tests only after positive screening. METHODS: We compared both strategies: 1) SAB only if positive screening with kits from manufacturer A, and 2) direct SAB from manufacturer B, and correlate their sensitivity with histological findings. RESULTS: We selected 118 kidney transplant recipients with a normal biopsy (n = 19), histological antibody-mediated damage (ABMR, n = 52) or interstitial fibrosis/tubular atrophy (IFTA, n = 47) following Banff 2015 and 2017 classification. Direct SAB detected DSA in 13 patients missed by screening. Strategy 1 detected DSA in 0% normal, 61.5% ABMR and 8.5% IFTA patients; percentages with strategy 2 were 5.2%, 78.8% and 14.8% (p=0.004). Strategy 2 identified DSA allowing full ABMR diagnosis in 17% cases missed by strategy 1. Thereafter, direct SAB from manufacturer A confirmed DSA in 46% DSA-positive cases with strategy 2 (55.5% ABMR cases). CONCLUSIONS: Luminex screening failed to identify clinically relevant HLA antibodies, hampering DSA detection in patients with possible ABMR. Direct SAB testing should be the chosen strategy for post-transplantation monitoring, albeit direct SAB from the two existing manufacturers may diverge in as much as 50% of cases.
Assuntos
Isoanticorpos/sangue , Transplante de Rim , Rim/patologia , Sorologia/métodos , Adulto , Idoso , Análise Custo-Benefício , Feminino , Fibrose , Antígenos HLA/imunologia , Teste de Histocompatibilidade , Humanos , Separação Imunomagnética , Masculino , Pessoa de Meia-Idade , Sorologia/economiaRESUMO
UNLABELLED: The Catalan Agency for Health Technology Assessment and Research (AETIM) proposed, in 2001, criteria for performing a bone densitometry (BD) for use in the consultations of the public health system. OBJECTIVE: To determine the sensitivity, specificity, positive predictive value and negative predictive value of the criteria to indicate BD. MATERIAL AND METHODS: Five groups of volunteers (premenopausal women aged 46 to 65 years, postmenopausal women aged 46 to 65 years, postmenopausal women aged> 65 years and men 46 to 65 years and> 65 years) underwent BD and a questionnaire on risk factors. The results obtained with the AETIM criteria are related to criteria for indication of BD proposed by the World Health Organization (1999 and 2003 criteria), the National Osteoporosis Foundation (1998 amd 2010 criteria) and the International Committee of Clinical Guidelines on Osteoporosis. RESULTS: Criteria from the Catalan Agency have low sensitivity to detect both low bone mass (T index<-1) and osteoporosis (T index<-2.5), specificity varied according to the group. The positive predictive value is low, but the negative predictive value for osteoporosis is high in all groups (except for postmenopausal women aged> 65 years). The remaining criteria have a high negative predictive value and, in women, good sensitivity and low specificity, especially for identifying patients with osteoporosis. CONCLUSION: Catalan Agency criteria are useful for selecting patients who would not need BD, but lack sufficient sensitivity to identify individuals with low bone mass. The other criteria also have a high negative predictive value for osteoporosis, and a better sensitivity.