Analysis of Quality Indicators of the Pre-Analytical Phase on Blood Gas Analyzers, Point-Of-Care Analyzer in the Period of the COVID-19 Pandemic.

AIM OF THE STUDY: We evaluated and compared blood gas analysis (EGA) non-conformities (NC) considered operator-dependent performed in Point-Of-Care (POC) analyzer as quality indicators (IQ) of the pre-analytical phase. To this end, four different NC registered in the resuscitation departments of the Hospital Polyclinic Bari from the beginning of the pandemic (March 2020) until February 2022 were evaluated. The results obtained were compared with those recorded in the pre-COVID period (March 2018-February 2020) to check if there were differences in number and type. MATERIAL AND METHODS: GEM 4000 series blood gas analyzers (Instrumentation Laboratory, Bedford, MA, United States) are installed with integrated Intelligent Quality Management (iQM®), which automatically identify and log pre-analytical errors. All blood gas analyzers are connected to the company intranet and interfaced with the GEM Web Plus (Werfen Instrumentation Laboratory, Bedford, MA, United States) data management information system, which allows the core laboratory to remotely supervise all decentralized POC stations. The operator-dependent process NC were expressed in terms of absolute and relative proportions (percentiles and percentage changes). For performance evaluation, the Mann-Whitney U test, Chi-squared test and Six-Sigma Metric calculation for performance classification were performed. RESULTS: In the COVID period, 31,364 blood gas tests were performed vs. 16,632 tests in the pre-COVID period. The NC related to the suitability of the EGA sample and manageable by the operators were totals of 652 (3.9%) and 749 (2.4%), respectively, in the pre-COVID and COVID periods. The pre-analytical phase IQs used did not show statistically significant differences in the two periods evaluated. The Sigma evaluation did not show an increase in error rates. CONCLUSIONS: Considering the increase in the number of EGAs performed in the two periods, the training procedures performed by the core laboratory staff were effective; the clinical users of the POC complied with the indications and procedures shared with the core laboratory without increasing the operator-dependent NCs. Furthermore, the core laboratory developed monitoring activities capable of guaranteeing the maintenance of the pre-analytical quality.

Evaluation of qualitative and quantitative taste alterations in COVID-19.

A large percentage of coronavirus disease 2019 (COVID-19) patients have taste dysfunction. Interleukin 6 (IL-6) levels in mild and moderate COVID-19 patients with the type (quantitative or qualitative) of taste disorders were compared in this observational study. The 208 COVID-19 patients (118 men and 90 women) revealing only taste dysfunctions as prodromic symptoms were classified as mild and moderate patients. Survey results were used to evaluate the taste disorder. The IL-6 levels were measured using a chemiluminescence assay. Statistical analysis was conducted using the Wilcoxon rank, Welch's, and Mann-Whitney tests. The findings revealed that neither the presence of dysgeusia or phantogeusia nor the perception of sour and salty, differed statistically significantly between moderate and mild patients (P > 0.05). But between moderate and mild patients, there were statistically significant differences in how umami, bitter, sweet, and parageusia were perceived (P < 0.05). There was an impairment of multiple tastes up to ageusia in patients with high IL-6 levels. The findings demonstrated that parageusia and dysfunctions in umami, bitter, and sweet taste perception can be indicators of more severe forms of COVID-19.

Determination of iFGF23 Upper Reference Limits (URL) in healthy pediatric population, for its better correct use.

Background: The measurement of Fibroblast growth factor 23 (FGF23) may be useful in the diagnosis and management of abnormal phosphate metabolism in both patients with preserved renal function or with chronic kidney disease (CKD). FGF-23 tests differ considerably by molecule assayed (iFGF23 or cFGF23), analytical performance and reference ranges. We establish iFGF23 Upper Reference Limits (URL) in apparently healthy pediatric individuals using automated immunochemiluminescent assay. Methods: We measured the levels of plasma iFGF23 from 115 samples from apparently healthy pediatric subjects [59 (51.3%) individuals were male; median age 10 years (range 1-18)] included in an observational study conducted at Policlinico University Hospital of Bari. The method used for the iFGF23 assay was immunochemiluminescent sandwich assay developed by DiaSorin on the Liaison XL platform. Statistical calculation of 95% reference interval, right-sided (CLSI C28-A3) and verification of age and sex covariables was performed for the calculation of the URL. Results: The URL concentration of iFGF23 was 61.21 pg/mL (58.63 to 63.71, 90% CI). No significant differences were found between the median concentrations of iFGF23 differentiated by sex and age. Conclusions: The dosage of iFGF23 is important both for the differential diagnosis of the various forms of rickets, and for the subsequent monitoring of the effectiveness of drug treatment. We have established the URL for the iFGF23 Liaison test in apparently healthy pediatric subjects. The availability of iFGF23 pediatric reference values will allow a better clinical use of the test.

Clinical impact of the troponin 99th percentile cut-off and clinical utility of myoglobin measurement in the early management of chest pain patients admitted to the Emergency Cardiology Department.

OBJECTIVE: To verify the clinical impact of different low cut-offs for troponin I/cardiac troponin I (99th percentile to 10% CV) and for myoglobin, in early risk stratification of patients with suspected acute coronary syndrome. METHODS: A total of 516 consecutive non-ST-elevation patients admitted to hospital were followed. The first measurement of cardiac markers was performed at the point-of-care in the Emergency Cardiology Department, using Stratus CS. The lowest cardiac troponin I concentration with a CV0.07 microg/l in the Emergency Cardiology Department (P>0.05). Using lowering cut-off values, the difference between the fraction of patients that was positive compared with the diagnosis according to European Society of Cardiology and American College of Cardiology criteria and had remained statistically significant (P<0.05) up to 0.03 microg/l (99th percentile upper reference limit) was considered (85 patients, 16.5%, n.s.). Relative operating characteristic analysis confirmed that the best clinical cut-off was related to the cardiac troponin I concentration that meets the 99th percentile upper reference limit. The diagnostic accuracy of myoglobin in detecting the minimum cardiac damage was significantly lower, independently from the cut-offs considered. CONCLUSION: The diagnostic accuracy in detecting myocardial damage early in the Emergency Cardiology Department improves when the 99th percentile is used as a decisional value of cardiac troponin I; the use of this cut-off makes the measurement of myoglobin unnecessary.

Integration between the tele-cardiology unit and the central laboratory: methodological and clinical evaluation of point-of-care testing cardiac marker in the ambulance.

The aim of this study was to identify patients with myocardial necrosis in pre-hospital phase during transport by ambulance, without ST-segment elevation (NSTE) on the ambulance ECG. The analytical performance of the i-STAT troponin I (cTnI) method was assessed. A total of 53 NSTE ambulance ECG patients admitted to hospital were followed. The ambulance had experimental software able to receive data from the i-STAT device and transmit it to a protected address and server. cTnI mean values from 2.0 to 34 microg/L showed a total CV of 3.0-5.6%. The detection limit was 0.016 microg/L. A mean cTnI concentration of 0.09 microg/L was associated with a CV of 8.0% (decision limit). The i-STAT cTnI method was linear for concentrations from 0 to 35 microg/L. There was no effect (p<0.05) of interfering substances. For point-of-care testing (POCT), cTnI was >0.09 microg/L in 20 AMI patients (91%). The median ambulance turnaround time (TAT) was 12 min and median hospital TAT was 40 min, a difference of 28 min. The high sensitivity of the i-STAT cTnI method integrated with tele-medicine procedures could play an important role in the management of acute coronary syndrome patients related to the pre-hospital phase (early diagnosis and treatment in the ambulance). These approaches may allow improvements in patient outcomes and continuous monitoring of the POCT network in the central laboratory, thus meeting quality requirements.

Prognostic value of brain natriuretic peptide in the management of patients receiving cardiac resynchronization therapy.

OBJECTIVE: To evaluate the role of brain natriuretic peptide (BNP) in predicting the progression of heart failure (HF) after cardiac resynchronization therapy (CRT). BACKGROUND: It has been shown that BNP predicts the prognosis and can guide the treatment of HF. METHODS: We studied 50 consecutive patients (61+/-10 years, 23 male) with HF (8 with ischaemic cardiomyopathy), NYHA class III, left bundle branch block, left ventricular ejection fraction (LVEF) 91.5 pg/ml had 89% sensitivity, 59% specificity, and negative and positive predictive values of 96% and 33%, respectively, for HF progression after 12 months. CONCLUSIONS: HF patients with high BNP values after 1 month of CRT have worse prognosis during follow-up. Therefore, in these patients other therapeutic options should be considered.

Analytical evaluation of the Dade Behring Dimension RxL automated N-Terminal proBNP (NT-proBNP) method and comparison with the Roche Elecsys 2010.

Methods to quantify B-type natriuretic peptide (BNP) and N-terminal-propeptide (NT-proBNP) in plasma or serum samples are well established. We assessed the analytical performance of the Dimension RxL NT-proBNP method (Dade-Behring). Evaluation of different sample types was carried out. Controls and heparin plasma pools were used to determine the detection limit, precision, and linearity. Sample stability and the effect of interfering substances on the NT-proBNP concentrations were evaluated. Agreement between Dimension RxL and Elecsys 2010 (Roche Diagnostics) NT-proBNP methods was assessed. The influence of age and sex on NT-proBNP concentrations was evaluated in healthy subjects. Heparin plasma should be the matrix of choice. The detection limit was 2.0 ng/L. The total imprecision was 2.6-3.6% for concentrations from 231 to 9471 ng/L; mean NT-proBNP concentrations of 21 and 15 ng/L were associated with coefficients of variation of 9.9% and 14.7%, respectively. The method was linear up to 32,650 ng/L. There was no effect of temperature, freeze-thaw cycles and interfering substances. A bias was detected when Dimension RxL and Elecsys 2010 NT-proBNP methods were compared. Age and sex were significantly and independently related to NT-proBNP concentrations. The Dimension RxL NT-proBNP method, like the Elecsys 2010, is suitable for routine use in the diagnosis of heart failure.

Proteomic approach to the diagnosis of acute coronary syndrome: preliminary results.

BACKGROUND: Cardiac multimarker strategy is recommended by the IFCC, ESC and the ACC for an early risk stratification in non-ST-segment elevation (NSTE) ECG patients with chest pain. A new approach, based on protein biochip array technology, performs simultaneously: cTnI, CK-MB, myoglobin, CAIII, GFBB and FABP using a single chip. METHODS: We evaluated the analytical performance of the Randox-Evidence Investigator -biochip cardiac panel according to IFCC recommendations and NCCLS guidelines; a preliminary clinical evaluation was carried out on chest pain NSTE ECG patients, to evaluate the accuracy of the multimarker approach in an early diagnosis of AMI, related to the final diagnosis (ACC/ESC criteria). RESULTS: Troponin, CK-MB and FABP methods provide reproducible within-run and between-day results (total % CVs from 5.9% to 9.7%), and myoglobin and CAIII methods showed the total % CVs from 16.4% to 25.8%. Our preliminary clinical data suggests that FABP had a better diagnostic performance (sensibility = 100%) than myoglobin (sensibility = 75%) to detect AMI in the first hours after the onset of the chest pain and myoglobin/CAIII ratio (specificity = 92.9%) improved the myoglobin specificity. CONCLUSIONS: Cardiac markers have different diagnostic roles and, in this contest, biochip technology could be an interesting approach supporting clinical expectations.

Integration between point-of-care cardiac markers in an emergency/cardiology department and the central laboratory: methodological and preliminary clinical evaluation.

To achieve rapid assessment of chest pain in emergency/cardiology departments, a short turnaround time for cardiac marker testing is necessary. Nevertheless, Total Quality Management principles must be incorporated into the management of point-of-care testing (POCT); in this setting we implemented the Stratus CS assay as POCT for cardiac markers in our emergency/cardiology department. The analytical performance of the troponin I method was evaluated; information connectivity between the Stratus CS data management system and the laboratory information system was implemented and practical training of testing personnel was carried out at the POCT site. A total of 41 non-ST-segment elevation patients admitted to the hospital were followed to evaluate the appropriateness of hospital admission, formulated on the basis of the cardiac troponin-I level measured at the POCT site by clinical staff. Our preliminary clinical data suggest that the high sensitivity of the Stratus CS troponin method could play an important role in the early identification of patients with acute myocardial infarction in a low to intermediate-risk population for acute coronary syndrome. Our POCT model suggests that the central laboratory could ensure that the POCT program remains in compliance with quality requirements. Nevertheless, our comparison studies suggest that the implementation of POCT requires a high level of integration between cardiologists and pathologists to guarantee appropriate interpretation of the monitoring results for suspected ACS patients.

Analytical evaluation of an automated immunoassay for cardiac troponin I: the Vidas Troponin I assay.

Cardiac troponin I (cTnI) is a sensitive and specific biochemical marker of myocardial damage. We assessed the analytical performance of the Vidas Troponin I assay (Biomerieux). Controls and serum pools were used to determine the precision, analytical sensitivity and linearity; 97.5 and 99.5 percentiles concentrations were determined from the reference population. Fifty corresponding samples of serum and plasma (lithium-heparin) were tested and the results compared. The in vitro stability of serum and plasma samples was assessed at 20 degrees C, 4 degrees C and -20 degrees C, respectively. Samples of serum were used to assess the agreement between the Vidas Troponin I method and the revised Dimension RxL cTnI method (Dade-Behring). The total imprecision (CVs) was 13.1-5.2% for concentrations ranging between 0.25 and 19.8 microg/l cTnI. The lower detection limit was <0.1 microg/l. The upper reference limit (97.5 and 99.5 percentiles) was 0.11 microg/l and 0.12 microg/l, respectively (CV > 10%). The assay was linear up to 21 microg/l. The concentrations in lithium-heparin plasma were higher compared to those of the matched serum samples. The study of the agreement between the Vidas and Dimension RxL cTnI assays showed a total concordance of 96% with a bias value of -0.042. The Vidas Troponin I test is a fast, precise and sensitive method for the determination of cTnI.