Molecular diagnostics by microelectronic microchips

B. Foglieni*, S. Stenirri, A. Brisci, L. Cremonesi, M. Ferrari,
*Unit of Genomics for Diagnosis of Human Pathologies, IRCCS H. San Raffaele, Milan

Biochimica Clinica: 2007; 31(5): 331-348 [Article in english]

ABSTRACT.
Molecular diagnostics are being revolutionized by the development of highly advanced technologies for DNA and RNA testing. One of the most important challenges is the integration of microelectronics to microchip-based nucleic acid technologies. The specific characteristics of these microsystems make the miniaturization and automation of any step of a molecular diagnostic procedure possible. This review describes the application of microelectronics to all the processes involved in a genetic test, particularly to sample preparation, DNA amplification and sequence variation detection.

Miglioramento dell’accuratezza della determinazione della creatinina mediante l’impiego di metodica enzimatica

I. Infusino*, P. Luraschi, C. Valente, Mauro Panteghini
*1Centro Interdipartimentale per la Riferibilità Metrologica in Medicina di Laboratorio (CIRME), Università degli Studi di Milano

Biochimica Clinica: 2007; 31(5): 349-352 [Article in italian]

ABSTRACT.
Accuracy improvement of creatinine measurement by the use of an enzymatic assay. The estimation of glomerular filtration rate (GFR) is considered the best index of kidney function. Laboratories may routinely report a GFR estimate from serum creatinine concentrations by applying the “four variables” Modification of Diet in Renal Disease study (MDRD) equation. The general implementation of this equation is, however, impaired by the use of different creatinine assays. In this study, we evaluate the impact of the introduction of an enzymatic assay (E) on trueness and imprecision of creatinine measurements in comparison with a kinetic alkaline picrate “compensated” method (AP). Trueness was evaluated by measuring creatinine concentrations of three commutable materials with target value assigned with gas chromatography-isotope dilution mass spectrometry, while the imprecision was estimated using a liquid-frozen control material during a eight-month working period for a total of approximately 300 measurements. For creatinine measurements we used four platforms (all from Roche Diagnostics), the Integra 800 and Modular P (for trueness evaluation), and the Hitachi 917 and Modular P (for imprecision study). The trueness of creatinine measurements was significantly better using E, mainly at physiological concentrations where the AP was unable to fulfil the desirable bias (+3.4%). The imprecision of creatinine measurements also decreased when E replaced AP. While only one out 16 monthly CVs by E was higher than the desirable goal (<2.2%), six monthly CVs by AP (37.5%) surpassed this limit. We conclude that, for suitable clinical usefulness of creatinine measurement, laboratories should consider to definitively replace AP with E.

Analisi in citometria a flusso dell’espressione della proteina zap-70 in pazienti affetti da leucemia linfatica cronica: linfociti separati o sangue intero?

Chiara Colombo, Pierluigi Tramacere
Servizio Universitario di Medicina di Laboratorio, Ospedale di Desio

Biochimica Clinica: 2007; 31(5): 353-358 [Article in italian]

ABSTRACT.
Flow cytometry analysis of protein zap-70 expression in patients with chronic lymphocytic leukemia: periferal blood mononuclear cells or whole blood? The analysis of cytoplasmic protein ZAP-70 expression in chronic lymphocytic leukemia (CLL) is considered an independent prognostic marker of disease progression. It can easily be assayed by flow cytofluorimetric technique, even if different results can be obtained using different methods. The purpose of this study was to verify if the use of different types of sample can also determine analytical variability. The flow cytometric expression of protein ZAP-70 was measured in 30 patients with CLL and 10 controls. A double determination was performed on whole blood and on peripheral blood mononuclear cells, according to the method using anti-CD19-PE antibody (IL) and anti-ZAP-70 AlexaFluor488 antibody (Caltag Laboratories). Using whole blood, the percentage of positive cells was more elevated that with the other sample type. For obtaining accurate results with whole blood, some procedural changes should be introduced, such as the avoidance of hemolysis and an increase in incubation time with the specific antibody.

Torna al Numero 4/2007 | Vai all'Indice di Biochimica Clinica

Per chi desidera pubblicare su BC, sono disponibili le Istruzioni per gli Autori
Per chi desidera sottoscrivere l'abbonamento a BC, è disponibile la Cedola di Registrazione

1997, BIOMEDIA srl, tutti i diritti riservati
The material on this site may not be reproduced or otherwise
used without the prior permission of BIOMEDIA.