Applicazione di regole di validazione dell’esame emocromocitometrico nel laboratorio analisi dell’ospedale di Desio

A. Cappellani*, F. Cappellini, F.M. Biella, F. Sciarini, C. Parma, G. Limonta, P. Mocarelli, P. Brambilla

*Servizio Universitario di Medicina di Laboratorio, Ospedale di Desio (MI)
Biochimica Clinica: 2009; 33(3): 234-38 [Article in italian]

ABSTRACT
Validation rules applied to blood cell count analysis at the clinical pathology laboratory of Desio hospital. The impact of the autoverification algorithm proposed in 2005 by the International Consensus Group for Hematology Review (ICGER) has been evaluated at the laboratory of Desio hospital. A preliminary study to establish the diagnostic performance of the flags involved in the algorithm was conducted using 1000 samples (500 random and 500 abnormal). The efficiency of the validation system was then evaluated on the 500 random samples. 22.2% of the samples were blocked by the violation of at least one rule, while the remaining 77.8% was validated. After verifying the real existence of morphological and quantitative cell abnormalities, the samples were classified in true-positive (19.8%), false-positive (2.4%), true-negative (74%), and false-negative (3.8%). Obtained data fully comply with the goal suggested by the ICGER.

NT-proBNP nei pazienti con dispnea acuta in medicina d’urgenza: quale livello decisionale?

A. Dolci*, R. Dominici, P. Villa, S. Guzzetti, M. Panteghini

*Laboratorio Analisi Chimico-Cliniche, Azienda Ospedaliera ‘Luigi Sacco’ e Cattedra di Biochimica Clinica e Biologia Molecolare Clinica, Università degli Studi, Milano

Biochimica Clinica: 2009; 33(4): 239-42 [Article in italian]

ABSTRACT
NT-proBNP in patients with acute dyspnoea admitted to the emergency department: which cutoff should we use?. The NT-proBNP determination plays a key role in the emergency setting to rule out acute heart failure (AHF) in patients presenting with acute dyspnoea. Particularly, in the PRIDE study using 450 ng/L as cutoff the marker showed a negative predictive value (NPV) of 99%. In this retrospective study, we evaluated 498 emergency department (ED) patients with acute dyspnoea (248 males; mean age, 77±12 years) by NT-proBNP determination (Roche Elecsys 2010) at admission. The final diagnosis of AHF was determined on the basis of clinical history, physical examination, electrocardiogram and chest X-ray, but without knowledge of NT-proBNP results. 306 patients (61.4%) were diagnosed as AHF and 192 as having dyspnoea of noncardiac origin. NT-proBNP was >450 ng/L in 295 AHF patients (sensitivity, 96.4%), while 102 patients without AHF had NT-proBNP <450 ng/L (specificity, 53.1%). NPV and positive predictive value (PPV) were 89.4% and 76.3%, respectively. As the obtained NPV was lower than that reported in the PRIDE study, we also evaluated the diagnostic accuracy of NT-proBNP using the cutoff of 300 ng/L, as suggested by the ICON study. Using this lower cutoff, NT-proBNP was positive in 300 AHF patients (sensitivity, 98.0%) and negative in 81 patients without AHF (specificity, 42.2%). NPV and PPV were 92.0% and 72.7%, respectively. While sensitivities obtained at two different cutoffs were not significantly different (P=0.32), the specificity using 450 ng/L was significantly higher (P=0.04). In conclusion, we confirmed that, using NT-proBNP for ruling out AHF in ED, 450 ng/L as cutoff performs better than 300 ng/L, showing similar NPV but improved specificity.

Diagnostica per alcol e sostanze stupefacenti connessa ad incidenti stradali

M. Brugia*, V. Scocco, A. Serpilli, E. Fuligni, M. Tocchini

*Laboratorio Analisi, Azienda Ospedali Riuniti, Ancona

Biochimica Clinica: 2009; 33(4): 243-44 [Article in italian]

ABSTRACT
Laboratory diagnosis of alcohol and drug abuse among injured drivers. We studied 203 adult subjects who had been injured and admitted to emergency department after a road accident between February and October 2008. 203 blood samples and 198 urine samples were analyzed. The blood and urine alcohol concentrations were screened by an enzymatic assay and positive specimens were confirmed by a gas-chromatographic mass spectometry method. The blood and urine drug concentrations were screened by immunoenzimatic assays and positive specimens were re-analyzed with biochip methodology. Blood alcohol concentrations exceeded 0.50 g/L in 40 subjects (19.7%) and were in the toxic range (>1.5 g/L) in 21 subjects. 22 (10.8%) subjects were positive for drugs (cannabis, opiates and cocaine). Four subjects showed positivity for both alcohol and drugs.

Determinazione dell’etilglucuronide nelle urine su analizzatore Siemens Advia 2400

V. Bianchi*, S. Piccinini, A. Raspagni, C. Arfini

*Laboratorio di Tossicologia e 2Dipartimento di Patologia Clinica, Azienda Ospedaliera Santi Antonio e Biagio e Cesare Arrigo, Alessandria

Biochimica Clinica: 2009; 33(4): 245-48 [Article in italian]

ABSTRACT
Determination of urinary ethylglucuronide on Siemens Advia 2400. Ethylglucuronide (EtG) is a minor ethanol metabolite, formed by uridine diphosphate-glucuronosyltransferase, an enzyme characterized by a genetic polymorphism. EtG is a direct marker of alcohol misuse, present in many body fluids, but usually measured in urine. Recently, a new immunoassay based on a monoclonal antibody has been introduced and could be applied to automated instruments. In this study, we evaluated the performance of this method on the Siemens Advia 2400. This assay has shown good performance in terms of limit of detection (0,058 mg/L), linearity (up to 4,5 mg/L), imprecision (within-run CV 1,8% and between-run CV 2,3% for a control material with EtG concentration near the cutoff), recovery (94-102%), and stability of reagents on board (at least 8 days). When measuring urine samples, the high absorbance after the addition of first reagent may influence the measurement. To avoid this problem, we measured the absorbance soon after mixing the sample with the first reagent, setting it to zero.


Esperienza di implementazione di un sistema automatico di verifica e validazione dei risultati in un laboratorio clinico

G.C. Guidi*, G. Poli, A. Bassi, L. Giobelli, P.P. Benetollo, G. Lippi

*Laboratorio di Analisi Chimico-Cliniche ed Ematologiche, Azienda Ospedaliera di Verona, Policlinico G.B. Rossi, Dipartimento di Scienze Morfologico-Biomediche, Università di Verona

Biochimica Clinica: 2009; 33(4): 249-54 [Article in italian]

ABSTRACT
Implementation of an automatic system for verification and validation of laboratory test results: a personal experience. The manual test validation is a time-consuming process largely influenced by individual skills and knowledge, which would require the constant presence of specialized professionals. To overcome these inherent shortcomings, we developed a new procedure encompassing automatic validation of test results and a system of remote wireless connection, which allows the laboratory professional “on call” to access, visualize and validate data outside the laboratory by using a laptop. This system also provides steps where preanalytical and analytical errors can be identified and dealt with. The procedure implemented, as well as its healthcare and organizational advantages, are described in the present article.

Sindrome di Gilbert e genotipo TATA-box: esperienze e prospettive

R. Pacciolla*, O. Turri, L. Ferri, H. Nadry, E. Banfi, G. Melzi d’Eril, M.L. Biondi

*Dipartimento di Medicina Chirurgia e Odontoiatria, Università degli Studi di Milano

Biochimica Clinica: 2009; 33(4): 255-57 [Article in italian]

ABSTRACT
Gilbert’s syndrome and TATA-box genotype: experience of work and perspectives. Gilbert’s syndrome is characterized by unconjugated nonhemolytic hyperbilirubinemia and mild intermittent jaundice. Its molecular basis results in a TA repeat insertion (TA7) in the TATA-box of the UDP-glucoronosyltransferase gene promoter (UGT1A). In 1999 we introduced the Gilbert’s syndrome genetic test to analyze the relationship between the genetic variant TA7 and the bilirubin concentration in a sample of 98 subjects from all Italian regions. From 1999 to 2008 we analyzed the polymorphism’s influence on bilirubin metabolism in a larger population (500 subjects) and evaluated the appropriateness of the genetic analysis requests in the Gilbert’s syndrome diagnostic procedure by comparing results with those of the previous study. The TA7 homozygous distribution was statistically different between the two groups (16.3% in the first vs. 54,0% in the second one; P=0.00001). The bilirubin concentrations were higher in TA7 homozygous subjects when compared with heterozygous and normal ones (TA7/TA7, 1.47 ± 0.67 mg/dL; TA6/TA6, 0,68 ± 0,29 mg/dL; P=0.009).

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