[Show abstract][Hide abstract] ABSTRACT: Cardiovascular disease is a major cause of morbidity and mortality among hemodialysis (HD) and peritoneal dialysis (PD) patients, and dyslipidemia plays an important role in its pathogenesis. In particular, small, dense LDL (sd-LDL) particles have been recently highlighted as an emerging cardiovascular risk factor. PD patients exhibit a more overtly abnormal lipid profile than HD patients, probably due to the metabolic interference of the peritoneal dialysis fluid. Statins are the main drugs for the treatment of dyslipidemia and they are able to decrease all LDL subclasses levels, but it remains unclear whether they can influence the proportion of sd-LDL. Only few studies regarding the effect of statins on the proportion of these particles have been performed in HD patients and, to our knowledge, no trials have been carried out in PD patients. Therefore, we compared the lipid profile and the proportion of sd-LDL in two populations of HD and PD patients. Our study suggests that statin therapy may be effective in reducing both the absolute amount and the proportion of sd-LDL in patients with a more overtly abnormal lipid profile, such as patients undergoing peritoneal dialysis. Statins do not seem to be effective in altering sd-LDL levels in patients undergoing hemodialysis with other factors that can influence LDL subtractions generation, such as hypertension and diabetes mellitus. If and when our results prove to be reproducible in large-scale studies, such studies should provide new insights into sd-LDL and its actual role in atherogenesis in patients undergoing hemodialysis or peritoneal dialysis.
Full-text · Article · Jan 2012 · Contributions to nephrology
[Show abstract][Hide abstract] ABSTRACT: Setting specifications for analytical quality is always difficult. The risk-management approach might be a way to do so. In this approach, the definition of the required analytical quality is based on the evaluation of patient risk. Risk derives from the probability of error and from the damage that such an error might cause.
Eight Italian laboratories took part in this experiment. Measurements of glucose and total calcium were taken as examples. Analytical quality was evaluated using a specific ring trial with a frozen serum pool and by means of internal quality-control data. The total allowable error was defined according to biological variation specifications. The probability of error was extracted from the imprecision and comparative bias data of each laboratory. The damage caused by a wrong result was evaluated using the absolute probability judgment approach.
According to the iso-risk plots (standardized hyperboles on a graph where the x-axis represents damage and the y-axis represents probability) for glucose, all the laboratories were working with an analytical quality that guaranteed low risk for patients. On the contrary, for total calcium none of the laboratories exhibited sufficient quality to guarantee low risk for patients, the presence of bias being the most relevant problem.
The results seem to demonstrate the applicability of the risk approach to the analytical phase, indicating a new possible way to define analytical quality targets.
No preview · Article · Sep 2011 · Clinical Chemistry and Laboratory Medicine
[Show abstract][Hide abstract] ABSTRACT: Rapid and reliable exclusion of acute myocardial infarction during emergency department triage is an important clinical need. The purpose of this study was to evaluate the potential role of copeptin, a marker of acute endogenous stress, together with high sensitive troponin-I for a rapid and early rule-out of acute myocardial infarction.
Copeptin and myoglobin were measured in 80 subjects presenting to the emergency department with chest pain and symptoms suggestive of acute myocardial infarction, 46 patients had a negative high sensitive troponin-I concentration at presentation, 3, 6 and 12 hours; whereas 34 patients had negative or very low high sensitive troponin-I at presentation, but rising troponin values at 3, 6 and 12 hours.
Copeptin was significantly higher in patients with evidence of myocardial damage (median 92.2 pmol/L vs 8.5 pmol/L, p < 0.0001). The area under the receiver-operating characteristic curve (AUC) for copeptin at initial presentation was 0.86 (95 % confidence interval, CI: 0.76 to 0.93), which was significantly higher than 0.68 (95% CI: 0.57 to 0.78, p < 0.05) for myoglobin but not significantly different from 0.88 (95% CI: 0.79 to 0.93) for high sensitive troponin-I. The combination of high sensitive troponin-I and copeptin resulted in an AUC of 0.94 (95% CI: 0.86 to 0.98), while the combination of high sensitive troponin-I and myoglobin results in an AUC of 0.89 (95% CI: 0.81 to 0.95).
Copeptin concentrations are more sensitive than myoglobin as an early marker of myocardial damage. Although copeptin provides significant incremental value on top of high sensitivity troponin-I, myoglobin does not.
Full-text · Article · Jan 2011 · Clinical laboratory
[Show abstract][Hide abstract] ABSTRACT: We examined association of inducible myocardial perfusion defects with cardiorenal biomarkers, and of diminished left ventricular ejection fraction (LVEF) with kidney injury marker plasma neutrophil gelatinase-associated lipocalin (NGAL). Patients undergoing nuclear myocardial perfusion stress imaging were divided into 2 groups. Biomarkers were analyzed pre- and poststress testing. Compared to the patients in the low ischemia group (n = 16), the patients in the high ischemia group (n = 18) demonstrated a significantly greater rise in cardiac biomarkers plasma BNP, NT-proBNP and cTnI. Subjects were also categorized based on pre- or poststress test detectable plasma NGAL. With stress, the group with no detectable NGAL had a segmental defect score 4.2 compared to 8.2 (P = .06) in the detectable NGAL group, and 0.9 vs. 3.8 (P = .03) at rest. BNP rose with stress to a greater degree in patients with detectable NGAL (10.2 vs. 3.5 pg/mL, P = .03). LVEF at rest and with stress was significantly lower in the detectable NGAL group; 55.8 versus 65.0 (P = .03) and 55.1 vs. 63.8 (P = .04), respectively. Myocardial perfusion defects associate with biomarkers of cardiac stress, and detectable plasma NGAL with significantly lower LVEF, suggesting a specific heart-kidney link.
[Show abstract][Hide abstract] ABSTRACT: recently, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) proposed a new equation for estimating glomerular filtration rate (eGFR), which could potentially replace the Modified Diet for Renal Disease Study (MDRD) equation in routine clinical use. Our aim was to evaluate the correlation between them and to compare the prevalence of each CKD stage using these two equations.
we measured serum creatinine in 38,188 consecutive patients and calculated eGFR using the CKD-EPI and MDRD equations. We also compared the distribution of CKD stages for both equations.
there was very good correlation between eGFR estimated by CKD-EPI and MDRD at values < 60 ml/min × 1.73 m2, but not at higher values. Estimated prevalence of CKD (eGFR < 60 ml/min × 1.73 m2) was 5.9% with CKD-EPI and 7.5% with MDRD. Furthermore, the prevalence of CKD Stage 2 was lower with CKD-EPI (33.8% vs. 49.1%. with MDRD).
the use of the CKD-EPI equation results in a lower estimated prevalence of CKD, compared to the MDRD equation. This may have important implications for public health and clinical practice, as well as for future modification of guidelines for laboratories.
No preview · Article · Nov 2010 · Clinical nephrology
[Show abstract][Hide abstract] ABSTRACT: Laboratory turnaround times (TATs) for urgent (Stat) tests are indicators of efficiency, and many clinicians consider prolonged TAT one of the most important causes for delay in transferring patients from emergency departments. Here, we present a review of the main proposed solutions, dependent on size, organization models and mission of the hospital. Although there is no clear evidence that laboratory TAT could be directly related to patient care, we need to continuously evaluate each laboratories performance by comparing them to patient outcomes.
No preview · Article · May 2010 · Clinical Chemistry and Laboratory Medicine
No preview · Article · Jan 2009 · The quarterly journal of nuclear medicine and molecular imaging: official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of...
[Show abstract][Hide abstract] ABSTRACT: The reference limits for thyroid antibodies are generally made by measuring thyroid peroxidase and thyroglobulin antibody values in a group of healthy subjects (direct method), as proposed by the National Academy of Clinical Biochemistry.
To define the upper reference limits of thyroid peroxidase and thyroglobulin, by using an indirect method to analyze data from a large number of outpatients that were stored in the information system of a general hospital laboratory.
Thyroid peroxidase and thyroglobulin values from 21 492 patients, who had undergone antithyroid antibody measurements, were retrieved from the laboratory information system; the upper reference limits (in the top 97.5 percentile) were calculated using the indirect Kairisto method, after exclusion of outliers.
The mean upper reference limits for females and males were 15 kIU/L and 9 kIU/L for thyroid peroxidase, and 21 kIU/L and 19 kIU/L for thyroglobulin, respectively. The upper limits showed minimal or no differences in the different age classes in either females or males.
Using a vast population of patients, we demonstrated that the upper limits for thyroid antibodies are much lower than the values obtained with classic, direct methods and that they do not vary in relation to age and sex.
Full-text · Article · Jan 2009 · Archives of pathology & laboratory medicine
[Show abstract][Hide abstract] ABSTRACT: High-pressure liquid chromatography instruments specifically devised for separating haemoglobin (Hb) fractions have been increasingly employed by the hospital laboratories over the recent years since they allow easy and fast screening for several Hb variants. Although such instruments may be proposed as sensitive, specific and reliable alternatives to the classic electrophoretic techniques, a major drawback of this screening strategy is the almost identical retention time of several Hb variants. In particular, at least 18 Hb variants have been reported in the same retention window as HbA(2), including HbE, the second most common beta-chain variant in humans after sickle cell trait. Recently, we evaluated the performance characteristics of an improved buffer formulation originally conceived for Hb variants separation procedures on the fully automated high-pressure liquid chromatography instrument Tosoh G7. At variance with other fully automated high-pressure liquid chromatography analyzers, the elution pattern on the G7 in subjects heterozygous for HbE is characterized by the presence of four suggestive peaks (HbF, HbA, HbA(2) and HbE), confirming the effective separation of HbE from HbA(2). Because of its potential value in the diagnosis of the thalassaemia syndromes, the effective separation of HbA(2) from HbE can provide clinical laboratories with a valuable information for the diagnostic reasoning.
No preview · Article · Nov 2008 · International Journal of Laboratory Hematology
[Show abstract][Hide abstract] ABSTRACT: Guidelines for the primary prevention of cardiovascular disease recommend the use of risk-assessment methods to identify high risk patients who can benefit from lifestyle changes and/or drug treatment. Although all these risk-prediction methods are based on the same principle, they produce different risk estimates. The aim of this study was to compare the most recent and widely used cardiovascular risk-prediction methods and the respective guidelines when applied to Italian cohorts.
Seven different risk-assessment methods were applied to two groups of subjects, 536 healthy individuals and 426 diabetic patients. Sensitivity and specificity of Framingham-based risk-assessment methods were calculated using the Framingham full equation as the reference standard. The extent of concordance among the different risk-assessment methods was determined by kappa test. By using NCEP-ATPIII risk calculator, modified Sheffield tables, Joint European Societies charts, Joint British Societies charts, Italian CUORE Project charts, European SCORE charts and New Zealand National Heart Foundation charts in the group of 536 healthy subjects, lipid-lowering treatment would be recommended in 17.5%, 12.7%, 12.1%, 8.6%, 5.0%, 4.7%, and 1.1% subjects, respectively. By using the same risk-assessment methods in the group of 426 diabetic patients, treatment would be recommended for 100%, 82.9%, 66.9%, 77.7%, 43.0%, 74.9%, and 47.4% patients, respectively. The Joint British charts and the modified Sheffield tables showed the closest agreement with the reference standard.
Our study confirms that the use of different risk-assessment methods in clinical practice can substantially change risk estimation and consequently statin prescription rate. The Framingham-based risk-assessment methods and particularly the NCEP-ATPIII guidelines select for lipid-lowering treatment a higher number of subjects than those identified according to European and Italian recommendations.
Full-text · Article · Jun 2007 · Nutrition, metabolism, and cardiovascular diseases: NMCD
[Show abstract][Hide abstract] ABSTRACT: The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers' instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.
No preview · Article · Apr 2007 · The International journal of biological markers
[Show abstract][Hide abstract] ABSTRACT: The assessment and management of congestive heart failure relies increasingly on the measurement of B-type natriuretic peptide (BNP). However, the effective contribution of this biochemical test in the clinical decision making is influenced by reliability of the measure, which also depends on several preanalytical issues. Since there is controversy on the influence of the matrix and the storage conditions on BNP measurement, we compared results of BNP in serum, K2 ethylene diamine tetra-acetic acid (EDTA) plasma and lithium heparin plasma fresh samples and in matching samples stored at -20 and -80 degrees C for 1 week. BNP measured on the Bayer Advia Centaur was systematically underestimated in heparin plasma (-47%) and serum (-62%) when compared to K2 EDTA plasma. According to the established 100 ng/L cutoff value, 25% and 37% of the fresh samples collected in heparin plasma or serum were misclassified from the reference K2 EDTA fresh specimen, respectively. When compared to the fresh specimens, the mean and interindividual bias observed for samples stored at either -20 degrees C or -80 degrees C was, overall, modest for K2 EDTA plasma (-2%) and heparin plasma (+6% and -4%, respectively), though it appeared clinically meaningful in serum (+47% and +28%, respectively). Although we can not rule out that other BNP assays using different antibodies may be not affected from degradation during storage to the same extent, results of our investigation demonstrate that K2 EDTA plasma is the most suitable specimens for BNP testing on fresh and frozen samples stored at either -20 degrees C or -80 degrees C for up to 1 week.
No preview · Article · Jan 2007 · Journal of Clinical Laboratory Analysis
[Show abstract][Hide abstract] ABSTRACT: Background. Preanalitical conditions strongly affect the measurement of the ammonia levels in plasma or serum, especially the time from drawing the blood sample to centrifugation. A refrigerate transport is recommended in association to the timeliness of the execution of the test. Aim of this study is to verify if the refrigeration preserves the blood integrity for the ammonia determination. Methods. we compared the results obtained from 3 blood samples of 19 healthy subjects, measured at time zero and after 120 min, stored a 4° and 25°C. Further, 3 blood samples from other 43 volunteers were evaluated after 3 hours of storage, at the same conditions. Results. the mean difference between t0 and t120 kept at 4°C was of 10.1 ± 6.3 μmol/L (95% CI: 7.1-13.1); p < 0.0001. The difference between not refrigerated and refrigerated samples, after 120 min, was 0.4 ± 3.5 μmol/L (95% CI: -1.3-2.1); p = n.s. The mean difference between tO and 1180 kept at 4°C was of 26.3 ± 10.9 μmol/L (95% CI: from 22.9 to 29.6); The difference between not refrigerated and refrigerated samples, after 180 min, was -1.4 ± 9.1 μmol/L (95% CI: from -4.2-1.3); p = n.s. Conclusions. The ammonia levels increase in the blood samples related to the time from the drawing. There are no differences in the ammonia concentration afters 120 and 180 min between the samples stored at 4 and 25°C. Refrigeration do not prevent the integrity of the blood samples for this test and a timeliness transfer of the samples to the laboratory is mandatory for an accurate measurement of the ammonia.
Full-text · Article · Apr 2006 · Rivista Italiana della Medicina di Laboratorio
[Show abstract][Hide abstract] ABSTRACT: It is known that the erythrocyte sedimentation rate is related to the erythrocyte concentration in blood. Recently, some authors have proposed a method for estimating the relation between the Westergren erythrocyte sedimentation rate and the erythrocyte sedimentation rate adjusted on an hematocrit of 0.35 L/L. In this study we firstly evaluated in 236 samples the relation between the erythrocyte sedimentation rate measured by the TEST 1 analyzer in samples corrected to 0.35 L/L of hematocrit and the erythrocyte sedimentation rate measured in undiluted samples, and the hematocrit and the hemoglobin concentration, obtaining a multiple correlation coefficient of 0.956; (p < 0.001). Comparison between the corrected for HCT erythrocyte sedimentation rate, measured vs estimated, showed a bias of 0.0 (0.95 CI: -0.98 to 0.98 mm/h) with an agreement limit +/- 14.5 mm/h. Then, the reference intervals for the estimated erythrocyte sedimentation rate at 0.35 L/L of hematocrit were calculated by means of an indirect method (Kairisto), using the one-year stored data (47810 results) in our laboratory database. Our data showed that the erythrocyte sedimentation rate corrected to 0.35 L/L of hematocrit could be estimated by a simple formula using the TEST 1 results; the reference ranges were higher than the reference ranges for uncorrected samples. New reference intervals were needed for an improved evaluation of the patients, and a table of reference intervals for age and sex is presented.
No preview · Article · Feb 2006 · Clinical laboratory
[Show abstract][Hide abstract] ABSTRACT: Riassunto "To err is human" sintetizza la natura umana dell'er-rore. La riduzione delle componenti umane nei pro-cessi diagnostici dovrebbe quindi aiutare alla ridu-zione del numero degli errori commessi. Si possono definire gli errori in medicina come il fallimento di azioni pianificate al fine di ottenere un obiettivo op-pure come l'utilizzo di pianificazioni sbagliate. L'au-tomazione agisce riducendo la prima causa, in quasi tutte le fasi del processo, dalle fasi preanalitiche (iden-tificazione dal campione, pretrattamento, accettabi-lità, ecc.) alle fasi post analitiche (autovalidazione, check, turn around time, ecc.). La fase analitica è stata la prima a beneficiare dell'automazione, diret-tamente sulle strumentazioni. Anche la fase pre-pre-analitica trae vantaggi, nella riduzione degli errori, dall'automazione: algoritmi diagnostici e test reflex possono essere implementati grazie alla congiunzio-ne della information technology all'automation tech-nology, migliorando l'appropriatezza. L'integrazione tra queste due componenti è la chiave di volta per sostenere processi diagnostici affidabili e sicuri. Summary Automation and lab errors prevention The sentence "To err is human" summarize the human natu-re of the error. Therefore, reducing human components would help to reduce the number of total error. We can define the error as a failure of a planned action to be com-pleted as intended or the use of the wrong plan to achieve the aim. Automation acts in the first cause of error, almost in all the phases, from preanalytical (sample identification, accessioning, etc.), to postanalytical (autovalidation, check, turn around time, etc.). The analytical phase was the first to benefit of automation, especially on the analyzers. Auto-mation processes can help also the pre-preanalytical phase in the error reduction: the implementation of diagnostic algorithms and reflex tests is permitted by the integration between information technology and automation techno-logy, improving the appropriateness. The integration betwe-en these two technologies is the keystone for reliable and safe diagnostic processes.