RESUMEN
Few reports have compared available serum free light chain (SFLC) assays. Here, a retrospective audit of the Freelite SFLC assay compared results to electrophoresis (EP)/immunofixation (IFX) and the N Latex FLC assay.A total of 244 samples collected over 3.5 months were studied using the Freelite and N Latex FLC nephelometry assays. Results were compared with serum and/or urine EP/IFX. The precision and linearity of the N Latex FLC assay was examined.Detectable paraprotein by serum or urine EP/IFX was present in 94% of samples with kappa and 100% with lambda FLC restriction. The correlation between the assays was higher for kappa (rhoâ=â0.97) than lambda (rhoâ=â0.89) especially when lambda results were above the upper limit of normal (rhoâ=â0.62). Agreement in the categorical diagnosis as measured by the Cohen's kappa statistic was good (0.70). The N Latex FLC assay displayed good precision and linearity. In discordant samples the Freelite and N Latex FLC assays had equivalent agreement with IFX.Traditional methods of EP/IFX detected paraproteins in the majority of cases. Correlation between the Freelite and N Latex FLC assay is better for kappa than lambda FLC. The two assays are not entirely equivalent. Care should be taken by interpreting physicians and laboratories considering switching assays.
Asunto(s)
Electroforesis/métodos , Inmunoensayo/métodos , Cadenas Ligeras de Inmunoglobulina/sangre , Cadenas Ligeras de Inmunoglobulina/orina , Paraproteinemias/diagnóstico , Anciano , Femenino , Humanos , Látex , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
The past decade has seen human leukocyte antigen (HLA) typing emerge as a remarkably popular test for the diagnostic work-up of coeliac disease with high patient acceptance. Although limited in its positive predictive value for coeliac disease, the strong disease association with specific HLA genes imparts exceptional negative predictive value to HLA typing, enabling a negative result to exclude coeliac disease confidently. In response to mounting evidence that the clinical use and interpretation of HLA typing often deviates from best practice, this article outlines an evidence-based approach to guide clinically appropriate use of HLA typing, and establishes a reporting template for pathology providers to improve communication of results.
Asunto(s)
Enfermedad Celíaca/epidemiología , Enfermedad Celíaca/genética , Antígenos HLA/genética , Prueba de Histocompatibilidad/estadística & datos numéricos , Australasia/epidemiología , Enfermedad Celíaca/sangre , Predisposición Genética a la Enfermedad/epidemiología , Predisposición Genética a la Enfermedad/genética , Antígenos HLA/sangre , Prueba de Histocompatibilidad/métodos , HumanosRESUMEN
We report the case of a 30-year-old woman who failed to achieve diagnostic Western blot criteria for HIV-1 infection until 21 months after her initial presentation. This case highlights the importance of suspecting delayed HIV seroconversion in cases with persistently indeterminant Western blots.
