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1.
Clin Chem Lab Med ; 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31927515

RESUMO

Background The comparability of thyroid-stimulating hormone (TSH) results cannot be easily obtained using SI-traceable reference measurement procedures (RPMs) or reference materials, whilst harmonization is more feasible. The aim of this study was to identify and validate a new approach for the harmonization of TSH results. Methods Percentile normalization was applied to 125,419 TSH results, obtained from seven laboratories using three immunoassays (Access 3rd IS Thyrotropin, Beckman Coulter Diagnostics; Architect System, Abbott Diagnostics and Elecsys, Roche Diagnostics). Recalibration equations (RCAL) were derived by robust regressions using bootstrapped distribution. Two datasets, the first of 119 EQAs, the second of 610, 638 and 639 results from Access, Architect and Elecsys TSH results, respectively, were used to validate RCAL. A dataset of 142,821 TSH values was used to derive reference intervals (RIs) after applying RCAL. Results Access, Abbott and Elecsys TSH distributions were significantly different (p < 0.001). RCAL intercepts and slopes were -0.003 and 0.984 for Access, 0.032 and 1.041 for Architect, -0.031 and 1.003 for Elecsys, respectively. Validation using EQAs showed that before and after RCAL, the coefficients of variation (CVs) or among-assay results decreased from 10.72% to 8.16%. The second validation dataset was used to test RCALs. The median of between-assay differences ranged from -0.0053 to 0.1955 mIU/L of TSH. Elecsys recalibrated to Access (and vice-versa) showed non-significant difference. TSH RI after RCAL resulted in 0.37-5.11 mIU/L overall, 0.49-4.96 mIU/L for females and 0.40-4.92 mIU/L for males. A significant difference across age classes was identified. Conclusions Percentile normalization and robust regression are valuable tools for deriving RCALs and harmonizing TSH values.

2.
Clin Chim Acta ; 496: 25-34, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31201817

RESUMO

BACKGROUND: The study aim is to compare cTnI values measured with three high-sensitivity (hs) methods in apparently healthy volunteers and patients admitted to emergency department (ED) with acute coronary syndrome enrolled in a large multicentre study. METHODS: Heparinized plasma samples were collected from 1511 apparently healthy subjects from 8 Italian clinical institutions (mean age: 51.5 years, SD: 14.1 years, range: 18-65 years, F/M ratio:0.95). All volunteers denied chronic or acute diseases and had normal values of routine laboratory tests. Moreover, 1322 heparinized plasma sample were also collected by 9 Italian clinical institutions from patients admitted to ED with clinical symptoms typical of acute coronary syndrome. The reference study laboratory assayed all plasma samples with three hs-methods: Architect hs-cTnI, Access hs-cTnI and ADVIA Centaur XPT methods. Principal Component Analysis (PCA) was also used to analyze the between-method differences among hs-cTnI assays. RESULTS: On average, a between-method difference of 31.2% CV was found among the results of hs-cTnI immunoassays. ADVIA Centaur XPT method measured higher cTnI values than Architect and Access methods. Moreover, 99th percentile URL values depended not only on age and sex of reference population, but also on the statistical approach used for calculation (robust non-parametric vs bootstrap). CONCLUSIONS: Due to differences in concentrations and reference values, clinicians should be advised that plasma samples of the same patient should be measured for cTnI assay in the same laboratory. Specific clinical studies are needed to establish the most appropriate statistical approach to calculate the 99th percentile URL values for hs-cTnI methods.


Assuntos
Síndrome Coronariana Aguda/sangue , Análise Química do Sangue/métodos , Serviço Hospitalar de Emergência , Voluntários Saudáveis , Limite de Detecção , Miocárdio/metabolismo , Troponina I/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Química do Sangue/normas , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Admissão do Paciente , Valores de Referência , Adulto Jovem
4.
Scand J Clin Lab Invest ; 79(4): 260-267, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30982358

RESUMO

The aim of the present study was to investigate serum HER2 extracellular domain (ECD) as a putative surrogate marker of the shedding phenomenon of HER2 receptor from the tumor tissue of primary breast cancer (BC) patients. A pilot retrospective study was conducted on 100 matched serum and tissue samples from patients with node-positive primary BC, stage II/III. Analysis of association and concordance between serum HER2 ECD levels (measured by chemiluminescence immunoassay) and the expression in matched tumor tissue of HER2 ECD and intracellular receptor domain (ICD) (determined by immunohistochemistry) were performed. The median serum HER2 ECD level was 9.4 ng/ml and cutoff values were set at 15.2 ng/ml or 13.0 ng/ml. HER2 ICD and ECD were overexpressed in tumor tissue of 19.8% and 6.9% of patients, respectively. Statistically significant associations were found between serum HER2 ECD levels and tissue expression of both HER2 ICD and ECD (p < .001; Fisher analysis). Moreover, strong concordances were found between serum HER2 ECD levels and tissue expression of HER2 ICD or ECD (cutoff 15.2 ng/ml: 80 and 92.5%, respectively). Our findings support a role for serum HER2 ECD as a surrogate marker of tissue HER2 status in primary BC, both for HER2 ICD or ECD expression.

5.
Clin Chim Acta ; 495: 161-166, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30978328

RESUMO

BACKGROUND: According to quality specifications required by international guidelines, the evaluation of the 99th URL value is a very difficult task that is usually beyond the capacity of a single laboratory. The aims of this article are to report and discuss the results of a multicenter study concerning the evaluation of the 99th percentile URL and reference change (RCV) of the ADVIA Centaur High-Sensitivity Troponin I (TNIH), recently distributed to the Italian clinical laboratories. MATERIALS AND METHODS: The reference population evaluated with ADVIA XPT method for the calculation of cTnI reference distribution parameters consisted of 1325 healthy adults subjects (age range from 18 to 86 years), including 653 women (mean age 50.7 years, SD 14.5 years) and 672 men (mean age 50.9 years, SD 13.8 years), well matched for both age (P = .8112) and sex (F/M = 0.97). RESULTS: cTnI distribution values of reference population was highly skewed, while log-transformed cTnI values roughly approximated a log-normal distribution. Men have higher cTnI values than women throughout all the adult lifespan. Moreover, the subjects with age ≤ 55 years had significantly lower cTnI values than those with age > 55 years (p < .0001). Of note, 62% of women and 77% of men had equal or higher than cTnI values than the LoD value of the method (i.e., 2.2 ng/L). CONCLUSIONS: The results of the present study demonstrate that the ADVIA Centaur High-Sensitivity Troponin I using the XPT automated platform fits both the criteria and quality specifications required by the most recent international guidelines for high-sensitivity methods for cTnI assay.


Assuntos
Análise Química do Sangue/normas , Miocárdio/metabolismo , Troponina I/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imunoensaio/normas , Masculino , Pessoa de Meia-Idade , Valores de Referência , Troponina I/metabolismo , Adulto Jovem
6.
Clin Chim Acta ; 493: 156-161, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30826369

RESUMO

BACKGROUND: The Italian Society of Clinical Biochemistry (SIBioC) and the Italian Section of the European Ligand Assay Society (ELAS) have recently promoted a multicenter study (Italian hs-cTnI Study) with the aim to accurately evaluate analytical performances and reference values of the most popular cTnI methods commercially available in Italy. The aim of this article is to report the results of the Italian hs-cTnI Study concerning the evaluation of the 99th percentile URL and reference change (RCV) values around the 99th URL of the Access cTnI method. MATERIALS AND METHODS: Heparinized plasma samples were collected from 1306 healthy adult volunteers by 8 Italian clinical centers. Every center collected from 50 to 150 plasma samples from healthy adult subjects. All volunteers denied the presence of chronic or acute diseases and had normal values of routine laboratory tests (including creatinine, electrolytes, glucose and blood counts). An older cohort of 457 adult subjects (mean age 63.0 years; SD 8.1 years, minimum 47 years, maximum 86 years) underwent also ECG and cardiac imaging analysis in order to exclude the presence of asymptomatic cardiac disease. RESULTS AND CONCLUSIONS: The results of the present study confirm that the Access hsTnI method using the DxI platform satisfies the two criteria required by international guidelines for high-sensitivity methods for cTn assay. Furthermore, the results of this study confirm that the calculation of the 99th percentile URL values are greatly affected not only by age and sex of the reference population, but also by the statistical approach used for calculation of cTnI distribution parameters.


Assuntos
Técnicas de Imagem de Sincronização Cardíaca/normas , Eletrocardiografia/normas , Troponina I/sangue , Troponina T/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Voluntários Saudáveis , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Valores de Referência , Adulto Jovem
8.
Clin Chem Lab Med ; 57(4): 521-531, 2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30218601

RESUMO

Background [-2]proPSA seems to outperform free/total prostate-specific antigen (PSA) ratio in prostate cancer diagnosis. However, [-2]proPSA stability remains an underestimated issue. We examined [-2]proPSA stability over time in whole blood before separation of serum and plasma and its implications for prostate health index (Phi) determination. Total PSA (tPSA) and free PSA (fPSA) stabilities were also assessed. Methods Blood was drawn from 26 patients and separated in two tubes for plasma (K2EDTA and K2EDTA plus protease inhibitors - P100) and one for serum (clot activator plus gel separator). Tubes were stored at room temperature before centrifugation 1, 3 and 5 h for serum and EDTA plasma or 1 and 5 h for P100 plasma. To investigate the influence of gel separator on markers' stability, blood was collected from 10 patients in three types of tubes to obtain serum: tubes with clot activator plus gel separator, with silica particles or glass tubes. Biomarkers were assayed with chemiluminescent immunoassays. Results [-2]proPSA and Phi levels significantly and progressively increased over time in serum (+4.81% and +8.2% at 3 h; +12.03% and +14.91% at 5 h, respectively, vs. 1 h; p<0.001). Conversely, [-2]proPSA levels did not change in plasma (EDTA or P100). tPSA levels did not change over time in serum or plasma, whereas fPSA decreased in serum. All markers were higher in plasma than in serum at any time point. This difference did not seem to be attributable to the use of gel for serum preparation. Conclusions EDTA prevented spurious in vitro modifications in PSA-related isoforms, confirming that a stabilized blood sample is a prerequisite for [-2]proPSA measurement and Phi determination.


Assuntos
Biomarcadores Tumorais/sangue , Antígeno Prostático Específico/sangue , Neoplasias da Próstata/sangue , Temperatura Ambiente , Idoso , Idoso de 80 Anos ou mais , Ácido Edético , Humanos , Imunoensaio , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico
9.
Clin Chem Lab Med ; 57(2): 259-267, 2018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30016276

RESUMO

Background The aims of this study were: (1) to calculate reliable thyroid stimulating hormone (TSH) reference intervals using laboratory databases; (2) to evaluate the relationship between TSH, sex and age values in different large Italian populations. Methods The TSH values stored in the laboratory information system of clinical laboratories of four Italian city hospitals, including 146,801 TSH measurements (with the respective age and sex data of individuals) were taken in consideration. Assuming a log-normal distribution, to log-transformed TSH values were applied the Dixon's iterative principle in order to exclude the outliers. At the end of this iterative process 142,821 log-transformed TSH results remained. The four clinical laboratories measured serum TSH concentrations using the same TSH immunoassay method (Access TSH 3rd IS, using UniCel DxI platform). Results The TSH reference interval calculated in the present study (0.362-5.280 mIU/L) is similar to that suggested by the manufacturer for the Access TSH 3rd IS assay (0.45-5.33 mIU/L). TSH values in females were significantly higher than in males (females: mean=2.06 mIU/L; standard deviation [SD]=1.26 mIU/L; n=101,243; males: mean=1.92 mIU/L; SD=1.19 mIU/L; n=41,578; p<0.0001). Moreover, a negative linear relationship was observed between TSH throughout all interval age values (from 0 to 105 years). Conclusions The results of the present multicenter study confirm that data mining techniques can be used to calculate clinically useful reference intervals for TSH. From a pathophysiological point of view, our results suggest that some Northern populations of Italy might still suffer some harmful effects on the thyroid gland due to mild to moderate iodine intake deficiency. Specific clinical trials are needed to confirm these results.


Assuntos
Tireotropina/sangue , Tireotropina/normas , Adulto , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Padrões de Referência
10.
Clin Chem Lab Med ; 56(3): 397-402, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29220884

RESUMO

It is well known that the results of immunoassay methods can be affected by specific or non-specific interferences, ranging from 0.4% to 4.0%. The presence of interference may greatly compromise the accuracy of immunoassay analyses causing an error in the measurement, producing false-positive or false-negative results. From a clinical point of view, these analytical errors may have serious implications for patient care because they can cause misdiagnosis or inappropriate treatment. Unfortunately, it is a very difficult task to identify the irregular analytical errors related to immunoassay methods because they are not detectable by normal laboratory quality control procedures, are reproducible within the test system, may be clinically plausible and are relatively rare. The first line of defense against erroneous results is to use in laboratory practice only immunoassay systems with the highest level of robustness against interference. The second line of defense is always taking into account the possibility of interference in immunoassay results. A correct approach should be addressed on identification of samples at high risk of interference. The attainment of this goal requires a critical review of the test result in relation to patient's clinical conditions and literature data, taking into account the analytical characteristics of the immunoassay system. The experts in immunoassay systems should make every effort to find some specific and reliable quality indicators for irregular analytical errors in order to better detect and monitor erroneous immunoassay results due to specific or non-specific interferences.


Assuntos
Técnicas de Laboratório Clínico , Erros de Diagnóstico , Imunoensaio , Humanos , Controle de Qualidade
11.
J Clin Lab Anal ; 32(3)2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28643405

RESUMO

AIM OF THE STUDY: To reassess the imprecision and Limit of Quantitation, to evaluate the cross-reaction with dehydroepiandrosterone-sulfate (DHEAS), the accuracy toward liquid chromatography-mass spectrometry (LC-MS) and the reference interval of the Access Testosterone method, performed by DxI immunoassay platform (Beckman Coulter). MATERIAL AND METHODS: Imprecision was evaluated testing six pool samples assayed in 20 different run using two reagents lots. The cross-reaction with DHEAS was studied both by a displacement curve and by spiking DHEAS standard in two serum samples with known amount of testosterone. The comparison with LC-MS was evaluated by Passing-Bablock analysis in 21 routine serum samples and 19 control samples from an External Quality Assurance (EQA) scheme. The reference interval was verified by an indirect estimation on 2445 male and 2838 female outpatients. RESULTS: The imprecision study showed a coefficient of variation (CV) between 2.7% and 34.7% for serum pools from 16.3 and 0.27 nmol/L. The value of Limit of Quantitation at 20% CV was 0.53 nmol/L. The DHEAS showed a cross-reaction of 0.0074%. A comparison with LC-MS showed a trend toward a slight underestimation of immunoassay vs LC-MS (Passing-Bablock equations: DxI=-0.24+0.906 LCMS in serum samples and DxI=-0.299+0.981 LCMS in EQA samples). The verification of reference interval showed a 2.5th-97.5th percentile distribution of 6.6-24.3 nmol/L for male over 14 years and <0.5-2.78 nmol/L for female subjects, in accord with the reference intervals reported by the manufacturer. CONCLUSIONS: The Access Testosterone method could be considered an adequately reliable tool for the testosterone measurement.


Assuntos
Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Testosterona/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromatografia Líquida/normas , Humanos , Imunoensaio/métodos , Imunoensaio/normas , Masculino , Espectrometria de Massas/normas , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
13.
Int J Biol Markers ; 32(4): e471-e473, 2017 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-28561878

RESUMO

Laboratory tests are frequently overused and have elevated inappropriateness rates. We previously developed a model to investigate the rate of utilization of tumor markers (TMs) in outpatients as an indirect indicator of inappropriateness. The model was based on the comparison between the number of actually ordered and expected tests, with the latter estimated on the basis of both epidemiological data and recommendations of available clinical practice guidelines.In this paper we propose an algorithm to distinguish prevalent cases without evidence of disease from those with metastatic spread, on the basis of both epidemiological and clinical information. The algorithm allows for a more precise prediction of the expected TM requests per year, to be compared with the actual number of requested TMs in order to assess possibly inappropriate overordering rates. Moreover, the implementation of the algorithm renders the epidemiologically based model more flexible to develop accurate indicators for appropriateness in the use of TMs in different stages of disease and for different clinical questions. A practical application with CA15.3 requests in breast cancer is presented.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Mucina-1/genética , Algoritmos , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/patologia , Feminino , Humanos
15.
Clin Chem Lab Med ; 55(11): 1722-1733, 2017 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-28245185

RESUMO

BACKGROUND: Systematic difference between thyroid-stimulating hormone (TSH) immunoassays may produce misleading interpretation when samples of the same patients are measured with different methods. The study aims were to evaluate whether systematic differences are present among TSH immunoassays, and whether it is possible to obtain a better harmonization among TSH methods using results obtained in external quality assessment (EQA) schemes. METHODS: Seven Italian clinical laboratories measured TSH in 745 serum samples of healthy subjects and patients with thyroid disorders. These samples were also re-measured by two reference laboratories of the study with the six TSH immunoassays most popular in Italy after 2 months of storage at -80 °C. Moreover, these data were compared to 53,823 TSH measurements, obtained by laboratories participant to 2012-2015 EQA annual cycles in 72 quality control samples (TSH concentrations from about 0.1 mIU/L to 18.0 mIU/L). TSH concentrations were recalibrated using a mathematical approach based on the principal component analysis (PCA). RESULTS: Systematic differences were found between the most popular commercially available TSH immunoassays. TSH concentrations measured by the clinical laboratories were very closely correlated to those measured with the same method by reference laboratories after 2 months of storage at -80 °C. After recalibration using the PCA approach the variation of TSH values significantly decreased from a median pre-calibration value of 13.53% (10.79%-16.53%) to 9.63% (6.90%-13.21%) after recalibration. CONCLUSIONS: Our data suggest that EQA schemes are useful to improve harmonization among TSH immunoassays and also to produce some mathematical formulas, which can be used by clinicians to better compare TSH values measured with different methods.


Assuntos
Imunoensaio/métodos , Tireotropina/sangue , Calibragem , Humanos , Imunoensaio/normas , Laboratórios/normas , Modelos Lineares , Análise de Componente Principal , Controle de Qualidade , Kit de Reagentes para Diagnóstico , Doenças da Glândula Tireoide/diagnóstico , Tireotropina/normas
16.
Clin Chim Acta ; 468: 105-110, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28189596

RESUMO

AIM OF THE STUDY: Recently, Beckman Coulter Diagnostics set up a new TSH immunoassay for the automated DxI platform. The aim of this study was to evaluate and compare the analytical performance and clinical results of this method with those of previous method. MATERIAL AND METHODS: A multicenter study (named TSH ELAS Study) was organized using 593 serum samples, collected from healthy subjects and patients with thyroid disorders, and 13 control samples, circulated in an External Quality Assessment (EQA) scheme. RESULTS: The values of LoB and LoD, and LoQ at 20% CV were 0.0004mIU/L, 0.001mIU/L and 0.0023mIU/L, respectively. Moreover, TSH concentrations >0.01mIU/L actually show imprecision values lower than 5% CV. This new TSH assay showed a systematic underestimation (on average of 6.25%) compared to old method, which is mainly due to larger differences between methods for samples with low TSH concentrations, related to the better analytical sensitivity of new compared to old method. In a reference population, including 279 apparently healthy adult subjects, Caucasian volunteers (mean age 43.6years, age 20-63years, 138 women and 141 males) the distribution of TSH concentrations was: mean (CI 95%) 1.694mIU/L (1.588-1.779), median 1.495mIU/L (1.412-1.588mIU/L), 97.5th percentile 3.707mIU/L. CONCLUSIONS: The new TSH immunoassay for DxI platform shows some relevant improvements compared to the previous one: use of the most recent WHO 3rd IRP 81/563 standard and monoclonal antibodies (instead of polyclonal antibodies of the old method), and better analytical sensitivities and reproducibility.


Assuntos
Imunoensaio/métodos , Tireotropina/sangue , Adulto , Automação , Estudos de Casos e Controles , Feminino , Humanos , Imunoensaio/normas , Masculino , Pessoa de Meia-Idade , Controle de Qualidade , Valores de Referência , Reprodutibilidade dos Testes , Neoplasias da Glândula Tireoide/sangue , Adulto Jovem
17.
Int J Biol Markers ; 31(3): e317-23, 2016 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26954072

RESUMO

BACKGROUND: Prostate-specific antigen (PSA) lacks specificity and sensitivity in discriminating prostate cancer (PCa) from benign prostatic hyperplasia (BPH) when the total PSA (tPSA) level is between 4 and 10 ng/mL. It remains to be investigated if additional tumor-associated molecules may improve the PCa diagnostic accuracy. The aim of the present study was to investigate whether serum levels of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3) and their combinations with PSA may enhance the diagnosis of PCa. METHODS: Serum tPSA and free PSA (fPSA) levels were measured using an automated chemiluminescence-based method. IGF1 and IGFBP3 levels were evaluated by radioimmunoassays in a prospectively and consecutively enrolled subset of 149 patients with tPSA ≤10 ng/mL made up of patients with benign prostatic hyperplasia (BPH; n = 113) and PCa (n = 36). RESULTS: IGF1 and IGFBP3 serum levels did not significantly differ between the PCa and BPH groups. No important correlation was found between the IGF molecules and PSA isoforms in both groups. Statistical analysis of the combination of markers indicated that only the free/total PSA ratio (f/tPSA%) was informative and independent in predicting the presence of PCa, considering that for high values of this percentage (17%) the probability of finding PCa decreased. Receiver operating characteristics areas under the curve (AUC) for IGF1 and IGFBP3 were not informative (AUC ~0.5 in both cases) contrary to the AUC for f/tPSA% (AUC = 0.689, p = 0.0002). CONCLUSIONS: The present study showed that neither IGF1 and IGFBP3 alone nor in combination with PSA enhance the diagnostic performance of PSA in PCa.


Assuntos
Biomarcadores Tumorais/sangue , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like I/metabolismo , Neoplasias da Próstata/sangue , Adolescente , Adulto , Idoso , Biomarcadores Tumorais/genética , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/genética , Adulto Jovem
19.
Scand J Clin Lab Invest ; 73(6): 480-4, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24015957

RESUMO

BACKGROUND: Sex hormone-binding globulin (SHBG) is the main transport protein of sex steroids. This study evaluated the analytical performance of the recently developed Access SHBG assay (Beckman Coulter) and compared it with other commercial methods for the determination of serum SHBG. Clinical validation was also performed. METHODS: Analytical performance including within-run and between-run imprecision was assessed for Access SHBG assay on the automated Beckman UniCel DxI800 analyzer. Linearity was assessed using five dilutions of the serum samples. For methods comparison, SHBG levels were determined also with Immulite 2000 analyzer (Siemens Healthcare) using clinical serum samples (n = 104). For clinical validation 135 specimens from healthy subjects, pregnant women, hypothyroid and hyperthyroid patients were analyzed. RESULTS: Total coefficients of variation were < 5.5%. Linearity test showed > 90% recovery for all samples and for all dilution rates. Comparison analysis (Bland-Altman difference analysis and Passing-Bablock regression) showed an acceptable agreement between selected methods. SHBG values measured by Access SHBG assay in different groups of subjects were in agreement with other clinical evidence. CONCLUSIONS: Automated Access SHBG assay appears to be a reliable and easy to perform assay, as necessary for application in routine diagnostics.


Assuntos
Globulina de Ligação a Hormônio Sexual/metabolismo , Adulto , Idoso , Automação Laboratorial , Análise Química do Sangue , Feminino , Humanos , Hipertireoidismo/sangue , Hipotireoidismo/sangue , Medições Luminescentes , Masculino , Pessoa de Meia-Idade , Pós-Menopausa , Gravidez , Pré-Menopausa , Valores de Referência , Adulto Jovem
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