Browsing by Issue Date, starting with "2023-04-14"
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- Deletional alpha-thalassemia and hematological phenotype: predictive parameters of different deletionsPublication . Gaspar, Gisela; Ramalho, Rita de Mira; Seuanes, Filomena; Feliciano, Carla; Duarte, Guida; Copeto, Sandra; Costa, Alcina; Santos, João Xavier; Miranda, ArmandinaIntroduction: Thalassemias are characterized by a quantitative imbalance of the globin chains due to the reduction or suppression of the synthesis of one of the globin chains.The hematological tests usually used as indicative for the investigation of α-thalassemia are the blood count with MCV (Mean Cell Volume) < 80 fL and/or MCH (Mean Cell Hemoglobin) < 27 pg and normal Hb A2 (< 3.5%). Aim: This study aimed to correlate the different deletional α-thalassemia genetic alterations with the corresponding hematological phenotype, based on casuistry from 2015 to 2019. Methodology: Was evaluated retrospectively 496 cases suspected of deletional α-thalassemia from 2015 to 2019 and correlated them with the hematological data available. We searched for α-thalassemia deletions by Gap-PCR and Multiplex Gap-PCR. Haematological evaluation was carried out by the erythrogram, Hb isoelectric focusing and quantification of Hb A2 and Hb F (Ion exchange high performance liquid chromatography). The statistical analysis of the results was carried out through calculating the mean, standard deviation, median, and t-Student test, with a significance level of 0.05. Results and discussion: Most patients (n=190) had a normal genotype (αα/αα), followed by heterozygosity (-α3.7/αα) (n=148) and homozygosity (-α3.7/α3.7) (n=141) for the 3.7kb deletion. We also detected 5 cases of heterozygosity for the 4.2Kb deletion (-α4.2/αα), 4 of double heterozygosity (α3.7/α4.2), 7 heterozygosity α0 (--SEA /αα) and 1 of HbH (--SEA/-α3.7). The results showed that the MCV and the MCH are excellent hematological indices for screening and selection of patients for molecular testing (their value being the lower the greater the number of deleted genes). Our results are in line with those described in the literature and reinforce that the cut-off value of 25 pg (MCH) is sensitive enough to infer the presence of α0 -thalassemia deletion. The detection of the α0 deletion is very important in preventing the occurrence of Hb Bart's in the offspring of a carrier couple. The diagnosis of deletional α-thalassemia is realised by genetic testing, however hematological indices are relevant predictive markers of the number of deleted alpha genes and the phenotype /genotype correlation.
- External Quality Assessment in Laboratory Safety Area (PNAEQ-1S Segurança Laboratorial 2023)Publication . Ventura, Catarina; Cardoso, Ana; Pires, Ana; Faria, AnaIntroduction: The National External Quality Assessment Program (PNAEQ) provides tools for carrying out external quality assessment in Laboratory Safety area. These tools allow the identification of occurrences and/or critical points in the operation, installations or equipment, that could have impact on the safety of patients and workers, beyond prioritize the necessary improvement actions. Objective: Presentation of the methodology implemented in PNAEQ in 2023, for the External Quality Assessment (EQA) in Laboratory Safety area.
- Biomarker of Chronic Alcohol Abuse – Carbohydrate-deficient Transferrin (CDT): Methodology VerificationPublication . Gomes, Filomena; Costa, Alcina; Fernandes, Lília; Silva, Ana Maria V. da; Vasconcelos, Miguel; Miranda, ArmandinaIntroduction: Transferrin is a glycoprotein synthesized in hepatocytes that can appear with different isomorphic forms in the plasma, acquiring different levels of sialization (1,2). In a healthy person, penta, tetra and trisial isoforms are detectible in plasma. However, in an alcohol abuse and/or dependence, asialo, monosialo and disialotransferrin isoforms are also present called carbohydrate-deficient transferrin (CDT) (3) . This is considered a specific biomarker of alcohol abusive and/or dependence, being useful in the diagnosis and monitoring of this pathology (4) . Aim: Verify compliance with the requirements of the manufacturer of the capillary electrophoresis method in laboratory practice and its suitability in determining the CDT. Materials and methods: The MiniCap System (Sebia) was used with calibrators traceable to the IFCC international reference procedure and normal and pathological internal control samples. Repeatability and intermediate precision tests were performed on control samples. From participation in External Quality Assessment (EQA) program (5 rounds - 2 samples each), Bias%, Deviation Index (DI) and Total Laboratory Error (TELab) were obtained. The Measurement Uncertainty was calculated by the Top Down Method (combined and expanded with a factor of 1.96), using the internal (CV%) and external (Bias%) quality control results. Results: In the repeatability tests, normal control samples (n=22, mean = 1.4%) were obtained, CV = 5.7%; for the pathological sample (n=24, mean = 5.4%), CV = 2.2%. In intermediate precision tests for the normal control sample, (n= 12, mean = 1.4%), CV = 6.7%; for the pathological sample (n=12, mean = 5.3%), CV = 4.9%. In samples from EQA program, mean Bias = -1.0% and TELab = 11.5. In the evaluation of the method by DI, 1 satisfactory, 7 good and 2 excellent results were obtained. The obtained Expanded Uncertainty (1.3% ± 0.3) is consistent with that indicated by the manufacturer. Conclusion: The TELab obtained meets Westgard`s desirable specifications (5) , being considered an appropriate methodology for use in laboratory practise for diagnosis. However, it is considered important to monitor the method with Internal Control samples, and participate in EQA programs, as well as periodic evaluation of Quality Indicators.