1,721,195 research outputs found
Harmonization of automated hemolysis index assessment and use: is it possible?
No full textThe major source of errors producing unreliable laboratory test results is the pre-analytical phasewith hemolysis accounting for approximately half of themand being the leading cause of unsuitable blood specimens. Hemolysis may produce interference in many laboratory tests by a variety of biological and analytical mechanisms. Consequently, laboratories need to systematically detect and reliably quantify hemolysis in every collected sample by means of objective and consistent technical tools that assess sample integrity. This is currently done by automated estimation of hemolysis index (HI), available on almost all clinical chemistry platforms, making the hemolysis detection reliable and reportable patient test results more accurate. Despite these advantages, a degree of variability still affects the HI estimate and more efforts should be placed on harmonization of this index. The harmonization of HI results from different analytical systems should be the immediate goal, but the scope of harmonization should go beyond analytical steps to include other aspects, such asHI decision thresholds, criteria for result interpretation and application in clinical practice as well as report formats.With regard to this, relevant issues to overcome remain the objective definition of a maximum allowable bias for hemolysis interference based on the clinical application of the measurements and the management of unsuitable samples. Particularly, for the latter a recommended harmonized approach is required when not reporting numerical results of unsuitable sampleswith significantly increasedHI and replacing the test resultwith a specific comment highlighting hemolysis of the sample
Free testosterone/cortisol ratio in soccer: usefulness of a categorization of values
No full textThe free testosterone:cortisol ratio (FTCR) is widely used for studying and preventing overtraining syndrome in various sports. The use of FTCR for following overtraining syndrome was proposed originally with two approaches: FTCR lower than 0.35x10(-3), calculated on free testosterone (FT) in nanomoles per liter (nmol/L) and on cortisol (C) in micromoles per liter (mmole/L) or a decrease of the ratio of 30% or more in comparison with the previous value. In our experience, the use of an absolute value as a threshold is not useful, whereas the evaluation of the concentrations of hormones and their ratio in comparison with previous ones is more useful. These classical approaches are not, however, sufficient to describe the various possible physiological modifications linked to training excess and/or incomplete recovery
The exciting story of cardiac biomarkers: from retrospective detection to gold diagnostic standard for acute myocardial infarction and more
No full textThis paper reviews the history of the contribution of the laboratory medicine to clinical cardiology and discusses the most important steps in this field. Until 20 years ago, the clinical laboratory only placed at the cardiologist's disposal a few assays for the retrospective detection of cardiac tissue necrosis, such as enzymatic methods for creatine kinase and lactate dehydrogenase activities. However, in the latter part of the 20th century, highly sensitive and specific assays, such as cardiac troponins, as well as assays for markers of myocardial function, such as cardiac natriuretic peptides, rapidly changed the scenario of clinical management of patients with cardiac diseases, assigning to the laboratory a pivotal role in the overall diagnostic flow. This is witnessed by the recent incorporation of these markers into international guidelines and in the redefinition of myocardial infarction. For the foreseeable future, new serum markers of myocardial ischemic, i.e. reversible, injury or related to coronary plaque instability and disruption are expected
Field evaluation of Spaplus system for the determination of free light chains (FLC)in serum
No full textBackground: Measurements of serum immunoglobulin k and λ FLC and FLC ratio calculation are recommended for the evaluation of plasma cell disorders. Several practical issues for
the analytical measurement of FLC have, however, been identified. Searching for a solution able to fulfil the performance goals for the effective use of FLC in clinical setting, we evaluated the suitability of SPAplus analyzer using Freelite reagents (both from The Binding Site) for FLC determination.
Particularly, we compared the system performance with allowable goals for bias, imprecision (CV) and total error (TE) derived from biologic variation of FLC.
Methods: We evaluated the performance of SPAplus FLC using data collected during a six-month time period of routine use,employing two different reagent lots. The two-level (N and H)
liquid SPAplus control material was used for bias estimate by comparing the obtained long-term experimental means (n=34, both levels) with the corresponding assigned values. The
protocol for CV evaluation employed the liquid-frozen Bio-Rad Liquichek Unassayed Chemistry Control, measured in each performed run for a total of 29 runs. Inaccuracy was checked by results from three UK NEQAS exercises (system-specific (SPAplus) consensus value as reference). Goals (desirable/minimum quality levels) for bias, CV and TE were
±4.1%/6.1%, <4.0%/6.0% and ±10.7%/16.1% for κFLC and ±7.1%/10.6%, <3.5%/5.3% and ±12.9%/19.3% for λFLC,respectively. In addition, CV and TE for FLC ratio should be <2.3%/3.4% and ±7.7%/11.6%.
Results: Average cumulative bias was -6.0% (control N) and - 6.2% (control H) for κFLC, and 4.3% (N) and 6.1% (H) for
λFLC, respectively. Overall CV resulted in 10.8% for κFLC
(mean 11.9 mg/L), 7.3% for λFLC (mean 13.6mg/L) and 8.8%
for FLC ratio (mean 0.9). On EQAS evaluation all λFLC and
two out of 3 results for κFLC were within the minimum
allowable TE, while the FLC ratio achieved the minimum goal
only in one exercise.
Conclusions: Considering our previous experience with other
analytical systems, the SPAplus solution undoubtedly
represents a significant step forward. A further improvement in
measurement imprecision (priority) and method alignment is
probably needed to fulfil the stringent analytical goals derived
from biologic variation
La misura delle proteine totali per la quantificazione del crioprecipitato è “evidence-based”? = Is the total protein measurement for cryocrit quantification evidence-based?
No full textAppropriatezza delle richieste di PSA libero in un servizio di Medicina di Laboratorio ospedaliero
No full textLa determinazione della frazione libera dell’antigene prostatico specifico (fPSA) è specificamente indicata nella diagnosi differenziale tra iperplasia prostatica benigna ed adenocarcinoma prostatico, qualora la concentrazione di PSA totale (tPSA) sia compresa nell’intervallo tra 4 e
10 μg/L e l’esplorazione rettale risulti negativa (1). Per valutare l’appropriatezza delle richieste di fPSA, abbiamo quindi verificato retrospettivamente la concentrazione di tPSA dei campioni pervenuti al nostro laboratorio per il
dosaggio di fPSA in due periodi di tre mesi ciascuno, nel primo e nel secondo semestre 2005. Su un totale di 5773 richieste di tPSA, 2247 (38.9%) erano associate a fPSA,
ma di queste solo 352 (15.7%) erano da considerarsi appropriate, mentre 1839 (81.8%) e 53 (2.5%), associate a concentrazioni di tPSA rispettivamente 10 μg/L, risultavano inappropriate. Il costo totale dei dosaggi non giustificati ammontava a C 8135 su base annua.
Analizzando la provenienza delle richieste, si rilevava che, su un totale di 902 determinazioni di tPSA in pazienti ricoverati, nel 9.7% dei casi era richiesto anche il fPSA, ma solo in un quarto di questi in maniera appropriata. Nelle richieste di provenienza ambulatoriale, per un totale di 4871 tPSA, ben 2160 (44.3%) associavano fPSA. Tuttavia, solo una quota significativamente minore (n=330), pari al 15%, era richiesta per valori di tPSA
compresi tra 4-10 μg/L; 1830 determinazioni di fPSA, pari ad un esborso annuo da parte del SSN (tariffa C 13.63 per test) di circa C 50.000, erano da ritenersi inutili.
Dall’analisi dei nostri dati emerge quindi la necessità di interventi mirati al miglioramento dell’appropriatezza delle
richieste di fPSA, soprattutto nei pazienti ambulatoriali nei quali, per un bacino di utenza come quello di un ospedale
metropolitano di media grandezza, il numero di esami inappropriati è pari a circa 300 al mese. Un intervento di “autoprescrizione” del fPSA da parte del laboratorio, con un approccio tipo “reflex testing” in seguito alla determinazione del tPSA, potrebbe dimostrarsi efficace nel ridurre gli sprechi.
(1) Lilja H et al. National Academy of Clinical Biochemistry Guidelines for the Use of Tumor Markers in Prostate Cancer. www.nacb.org, 2006
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