Application of Six Sigma Metrics to Improve Quality Control for Point-of-care Glucose Testing / 이화의대지

Objectives@#Six sigma is a quality management system for the assessment of precisionand accuracy. We aim to apply the six sigma rule to quality control (QC) of point-of-care(POC) glucose meters in a tertiary hospital. @*Methods@#Thirty POC glucose meters installed at Ewha Womans University MokdongHospital were monitored between January 2013 and March 2014. The QC data fromthe POC glucose meters at low and high levels were collected. The monthly mean, standarddeviation, bias, coefficient of variation, and mean sigma metrics were calculated.The correlation between accuracy and precision was assessed based on the percentagebias and coefficient of variation. Comprehensive instructions on the QC and maintenanceof the devices were provided in the departments with poor sigma scores. Afollow-up assessment was performed after the intervention. @*Results@#The mean sigma values for the low and high controls were 3.29 and 3.71, respectively.At the low and high controls, 36.6% and 10% of the glucose meters showeda sigma value <3. The causes of low sigma values included the use of expired controlmaterials, prolonged air exposure of the sample strip, lack of user training, and errors indevice maintenance. On follow-up monitoring for 3 months following QC intervention,23.3% (low control) and 6.6% (high control) of the glucose meters scored a sigma value<3, indicating improved QC. @*Conclusion@#Sigma metrics-based QC can successfully improve accuracy and precisionof POC glucose meters in an objective and quantitative manner and can be usedfor follow up after QC intervention.

A Clue to Discovering Unstable Hemoglobin Variants via Abnormal WBC Differential Scattergrams Using the Sysmex Automated Hematology Analyzer

Incidentally, hemoglobin (Hb) variants can be detected using HbA1c tests in clinical laboratories. We found 38 patients with Hb variants after reviewing a total of 29,398 HbA1c test results from January 2017 to December 2017. While reviewing the complete blood count results of the patients (N=36) using the Sysmex XN-9000 analyzer (Sysmex, Japan), 35 patients were flagged as unremarkable with respect to differential white blood cell (WBC) counts. However, 1 patient with a normal WBC count did not obtain a differential WBC count while being flagged for an abnormal WBC scattergram in the white blood cell differential (WDF) channel. The WBC histogram showed an abnormally low fluorescent signal in the WDF channel; however, the differential WBC count was normal upon microscopic examination. After testing the patient's buffy coat suspended in normal saline and removing red blood cells (RBCs), the WBC scattergram and differential WBC count returned to normal. This finding suggests that the presence of a patient's RBCs may affect WBC scattergrams and Hb variants may interfere with the fluorescent dye in the differential WBC count. Therefore, when an abnormal WBC scattergram with an abnormally low fluorescent signal is encountered on the Sysmex XN-9000 analyzer, the presence of an Hb variant can be suspected.

GATA1 Expression in BCR/ABL1-negative Myeloproliferative Neoplasms

BACKGROUND: This study aimed to determine GATA1 expression levels to better characterize subgroups in BCR/ABL1-negative myeloproliferative neoplasms (MPNs). METHODS: This study enrolled 49 patients diagnosed as having BCR/ABL1-negative MPN on the basis of the 2016 World Health Organization classification : nine polycythemia vera (PV), 17 essential thrombocythemia (ET), 12 prefibrotic primary myelofibrosis (prePMF), and 11 overt primary myelofibrosis (PMF). Relevant clinical and laboratory data were retrieved from the medical records. The molecular analysis of CALR and MPL mutations and quantification of JAK2 V617F allele burden were performed. GATA1 expression was assessed by an immunohistochemical assay on bone marrow biopsy. GATA1 expression was analyzed serially in 18 patients. RESULTS: GATA1 expression decreased significantly in PMF compared with that in other subtypes, while no statistical difference was identified between ET and prePMF. GATA1 expression did not differ according to the mutation profiles or the allele burden of JAK2 V617F, but it decreased significantly in patients with overt fibrosis or leukemic transformation. CONCLUSIONS: Our results suggest that GATA1 expression is significantly low in PMF and decreases with progressive fibrosis and possibly with leukemic transformation, although our attempt to accurately distinguish between subgroups using GATA1 immunohistochemical approach did not achieve statistical significance. A large patient cohort with long term follow-up is required to evaluate the prognostic value of GATA1 expression.

Performance Evaluation of the Point-of-Care Cardiac Troponin T Assay

BACKGROUND: The point-of-care (POC) troponin T assay has been used in various clinical settings. Recently, a POC troponin T assay with an extended measurable range (40 ng/L-2,000 ng/L) was introduced. We aimed to evaluate the analytical performance of the Roche Cardiac POC Troponin T assay (POC TnT, Roche Diagnostics, Switzerland) using the cobas h 232 POC system. METHODS: The repeatability and within-laboratory imprecision of the POC TnT assay were evaluated using the Roche Cardiac POC Troponin T level 2 control. Repeatability was also assessed using patient samples. Linearity of the POC TnT assay was evaluated using patient samples containing five different concentrations of troponin T. Performance of the Elecsys Troponin T high sensitivity assay (hs-TnT) was compared with that of the POC TnT assay using 40 patient samples. RESULTS: The repeatability (%CV), and within-laboratory imprecision (%CV) using the level 2 control solution (mean troponin T, 441.6 ng/L) were 8.5% and 8.6%, respectively. The repeatability of patient samples containing 88.7 ng/L and 454.6 ng/L TnT was 7.5% and 7.2%, respectively. The POC TnT assay was confirmed to produce linear data between 54.0 ng/L and 1,347.7 ng/L. Relative to the hs-TnT assay, the Passing-Bablok linear regression equation (correlation coefficient) was y=0.8933x+6.24 (r=0.988). At a troponin T concentration of 40 ng/L, the estimated bias of the POC TnT assay was 1.972 ng/L (4.93%). CONCLUSIONS: Our data suggest that the Roche Cardiac POC Troponin T assay is reliable in cases where POC troponin T testing is required.

Evaluation of the 1B Equation to Estimate Glomerular Filtration Rate in Pediatric Patients with Cancer

The 1B equation is recommended for calculating the glomerular filtration rate (GFR) in children. Since few reports have evaluated the performance of the 1B equation, we investigated the performance of estimated GFR (eGFR) equations with the blood urea nitrogen (BUN) variable for pediatric cancer patients. In total, 203 children with cancer who underwent measured GFR (mGFR) assessment were enrolled. The median (range) mGFR and eGFR calculated using the updated Schwartz equation were 118 (43–241) and 135 (34–257) mL/min/1.73 m², respectively. The bias, precision (root mean square error [RMSE]), and accuracy (P30, mGFR±30%) of three eGFR equations including updated Schwartz, 1B, and full age spectrum (FAS) were compared. The median bias (mL/min/1.73 m²) was: updated Schwartz, 8.5; 1B, −9.0; and FAS, 4.2. The biases for all three eGFR equations were significantly different from zero. The P30 was: updated Schwartz, 63.5%; 1B, 66.0%; and FAS, 66.0%. The RMSE was the lowest for the 1B equation (40.4), followed by FAS (42.3), and updated Schwartz (45.5). The median eGFR/mGFR ratio for the eGFR equations decreased with age and reduced kidney functions (i.e., increased creatinine and BUN concentrations). The bias may be further reduced by using the average from two equations, such as the updated Schwartz and 1B, or FAS equation, rather than using the updated Schwartz or 1B equation alone. The use of the 1B equation may underestimate the GFR. Using creatinine and BUN variables in the eGFR equation may yield a more accurate estimate of the GFR in pediatric cancer patients.

Accuracy Assessment of Five Equations Used for Estimating the Glomerular Filtration Rate in Korean Adults

BACKGROUND: We aimed to assess the performance of the five creatinine-based equations commonly used for estimates of the glomerular filtration rate (eGFR), namely, the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPIcr), Asian CKD-EPI, revised Lund–Malmö (revised LM), full age spectrum (FAS), and Korean FAS equations, in the Korean population. METHODS: A total of 1,312 patients, aged 20 yr and above who underwent ⁵¹Cr-EDTA GFR measurements (mGFR), were enrolled. The bias (eGFR–mGFR) and precision (root mean square error [RMSE]) were calculated. The accuracy (P30) of four eGFR equations was compared to that of the CKD-EPIcr equation. P30 was defined as the percentage of patients whose eGFR was within±30% of the mGFR. RESULTS: The mean bias (mL·min⁻¹·1.73 m⁻²) of the five eGFR equation was as follows: CKD-EPIcr, -0.6; Asian CKD-EPI, 2.7; revised LM, -6.5; FAS, -2.5; and Korean FAS, -0.2. The bias of the Asian CKD-EPI, revised LM, and FAS equations showed a significant difference from zero (P<0.001). The RMSE values were as follows: CKD-EPIcr, 15.6; Asian CKD-EPI, 15.6; revised LM, 17.9; FAS, 16.3; and Korean FAS, 15.8. There were no significant differences in the P30 except for the Asian CKD-EPI equation: CKD-EPIcr, 76.6%; Asian CKD-EPI, 74.7%; revised LM, 75.8%; FAS, 76.0%; and Korean FAS, 75.8%. CONCLUSIONS: The CKD-EPIcr and Korean FAS equations showed equivalent analytical and clinical performances in the Korean adult population.

Prognostic Implications of Elevated Cardiac Troponin T in Patients with Acute Ischemic Stroke

BACKGROUND: Elevated cardiac troponin T (cTnT) levels have been reported in patients with acute ischemic stroke, however, the prognostic relevance is not well established. We evaluated the association between cTnT elevation and prognosis in patients with acute ischemic stroke. METHODS: The 182 consecutive patients enrolled had new-onset acute ischemic stroke. Their clinical and laboratory findings were collected retrospectively. Stroke severity and prognosis were determined using the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS) scores, as well as 30-day all-cause mortality. The patients were divided into two groups according to their cTnT levels: ≤14 and >14 ng/L. Cox proportional hazards regression analysis was performed to determine the associations between clinical or laboratory variables and 30-day all-cause mortality. The Kaplan-Meier method was used to compare the overall survival rate in patients with elevated and normal cTnT levels. RESULTS: The cTnT level was elevated in 14.8% of the patients. Age, NIHSS and mRS scores, creatinine kinase-MB, and 30-day all-cause mortality were significantly higher in patients with elevated cTnT levels than in those with normal cTnT levels. The hazard ratio of the elevated vs. normal cTnT group for 30-day all-cause mortality was 8.06 (95% confidence interval: 1.13-57.25, P=0.037). A Kaplan-Meier survival analysis revealed a significantly higher survival rate in patients with normal cTnT levels compared to those with elevated cTnT levels (P<0.0001). CONCLUSIONS: An elevated cTnT level is significantly associated with poor short-term outcomes in patients with acute ischemic stroke.

Diagnostic Utility of Serum Glycated Albumin for Diabetes Mellitus and Its Correlation With Hyperlipidemia

BACKGROUND: Glycated albumin (GA) is a better marker of short-term glycemic control than glycated hemoglobin (A1c). Dyslipidemia is the main cause of cardiovascular complications in diabetes mellitus (DM). Studies on the correlation of GA with lipid indices are sparse. We investigated the diagnostic utility of GA for DM and its relationship with serum lipid profiles compared with that of A1c. METHODS: The GA enzymatic method was used to determine the diagnostic utility of GA for DM by using samples from 163 normal subjects (group 1) and 102 patients newly diagnosed with type 2 DM (T2DM; group 2). To analyze the lipid profiles, 263 patients with T2DM receiving treatment (group 3) were recruited. RESULTS: GA correlated with A1c (r=0.934, P<0.0001). Linear regression analysis indicated that GA levels were about 2.48 folds those of A1c. In the ROC analysis for GA to diagnose DM, the areas under the curve (0.988, 95% confidence interval 0.972-1.004) was excellent. HDL levels were significantly lower in groups 2 and 3. In group 1, positive correlations were observed between A1c and triglyceride (TG), total cholesterol (TC), LDL, TG/HDL, TC/HDL, and LDL/HDL levels. A negative correlation was observed between HDL and A1c levels. In group 3, HDL levels (P=0.0124 and P=0.0141, respectively) were significantly higher and LDL levels tended to be lower, not statistically significant, in the well-controlled group categorized using the A1c and GA cut-off values. CONCLUSIONS: GA is a potential diagnostic tool for DM. Compared with A1c, GA seems less relevant to dyslipidemia.

Clinical Usefulness of Bronchoalveolar Lavage Cellular Analysis and Lymphocyte Subsets in Diffuse Interstitial Lung Diseases

BACKGROUND: Diffuse interstitial lung diseases (DILDs) form a part of a heterogeneous group of respiratory diseases. Bronchoalveolar lavage (BAL) analysis has been used for differential diagnosis of DILDs, but their clinical usefulness is controversial. The aim of this study was to investigate the clinical usefulness of BAL cellular analysis with lymphocyte subsets for the differential diagnosis of DILDs. METHODS: A total of 69 patients diagnosed with DILDs were enrolled. Basic demographic data, BAL cellular analysis with lymphocyte subsets, histology, and high resolution computed tomogram (HRCT) findings were analyzed and compared as per disease subgroup. RESULTS: Significant differences were found between groups in the proportion of neutrophils (P=0.0178), eosinophils (P=0.0003), T cells (P=0.0305), CD4 cells (P=0.0002), CD8 cells (P<0.0001), and CD4/CD8 ratio (P<0.0001). These findings were characteristic features of eosinophilic pneumonia and sarcoidosis. Other parameters were not significantly different between groups. At the cut-off value of 2.16 for sarcoidosis, CD4/CD8 ratio showed sensitivity of 91.7% (95% CI, 61.5-98.6%) and specificity of 84.2% (95% CI, 72.1-92.5%). CONCLUSIONS: Routine analysis of BAL lymphocyte subset may not provide any additional benefit for differential diagnosis of DILDs, except for conditions where BAL is specifically indicated, such as eosinophilic pneumonia or sarcoidosis.

Assessment of Therapeutic Drug Monitoring of Vancomycin in Elderly Patients According to New Guidelines

BACKGROUND: Concerns regarding increasing microbial resistance to vancomycin have resulted in recommendations for a higher trough serum vancomycin concentration. This study aimed to assess the dosage guidelines targeting vancomycin trough concentrations of 15-20 mg/L. METHODS: About 216 adult patients (age, >60 yr) were treated with intravenous vancomycin. The patients were divided into 2 groups according to their target vancomycin trough concentrations: the previous guideline group (n=108) treated with targeted vancomycin trough concentrations of 5-15 mg/L from Jan 2009 through April 2011 and the new guideline group (n=108) treated with targeted concentrations of 15-20 mg/L from November 2011 through July 2012. RESULTS: The 2 groups were not significantly different with respect to age, weight, initial serum creatinine, initial creatinine clearance, predictive trough levels, doses, serum drug concentrations, and area under the curve/minimal inhibitory concentrations. Regarding the proportions of vancomycin trough concentrations, the target range was achieved in 50% in the previous guideline group and in 16% in the new guideline group. In the previous and new guideline groups, the trough concentrations of 10-20 mg/dL were observed in 32.4% and 52.8% patients, respectively, and those of <10 mg/L were observed in 45.4% and 29.6%, respectively. CONCLUSIONS: Compared to the previous guideline group, the new guideline group showed higher proportions in the therapeutic range of 10-20 mg/L and lower proportions in trough concentrations <10 mg/L. The strictly managed vancomycin therapeutic drug monitoring in the new guideline group was assessed as more effective.

A Case of IgM Deficiency with B Cell Deficiency Detected by ABO Discrepancy in a Patient with Acute Osteomyelitis

ABO discrepancy refers to an inconsistency between red cell and serum typings and has various causes, including hypogammaglobulinemia. IgM deficiency is a rare disorder that may accompany several conditions such as infection and autoimmune disorders. Here, we describe a case of IgM deficiency discovered during the evaluation of an ABO discrepancy in a 16-yr-old Korean boy. ABO blood grouping showed that while his cell type was O+, serum typing detected only anti-A (3+). Anti-B was not detectable at room temperature but was graded at 1+ at 4degrees C. ABO genotyping revealed an O/O genotype. His serum IgG, IgA, and IgM concentrations were 770 mg/dL (reference range: 800-1,700 mg/dL), 244 mg/dL (reference range: 100-490 mg/dL), and 13.5 mg/dL (reference range: 50-320 mg/dL), respectively. He was diagnosed with acute osteomyelitis on the basis of clinical presentation and imaging studies. The symptoms gradually improved within 3 weeks of treatment. However, the ABO discrepancy and IgM deficiency persisted even 6 months after recovery and lymphocyte subset analysis revealed CD19+ B cell deficiency. To the best of our knowledge, IgM deficiency detected by ABO discrepancy in a patient with acute osteomyelitis has not been reported before.

A Case of IgM Deficiency with B Cell Deficiency Detected by ABO Discrepancy in a Patient with Acute Osteomyelitis

ABO discrepancy refers to an inconsistency between red cell and serum typings and has various causes, including hypogammaglobulinemia. IgM deficiency is a rare disorder that may accompany several conditions such as infection and autoimmune disorders. Here, we describe a case of IgM deficiency discovered during the evaluation of an ABO discrepancy in a 16-yr-old Korean boy. ABO blood grouping showed that while his cell type was O+, serum typing detected only anti-A (3+). Anti-B was not detectable at room temperature but was graded at 1+ at 4degrees C. ABO genotyping revealed an O/O genotype. His serum IgG, IgA, and IgM concentrations were 770 mg/dL (reference range: 800-1,700 mg/dL), 244 mg/dL (reference range: 100-490 mg/dL), and 13.5 mg/dL (reference range: 50-320 mg/dL), respectively. He was diagnosed with acute osteomyelitis on the basis of clinical presentation and imaging studies. The symptoms gradually improved within 3 weeks of treatment. However, the ABO discrepancy and IgM deficiency persisted even 6 months after recovery and lymphocyte subset analysis revealed CD19+ B cell deficiency. To the best of our knowledge, IgM deficiency detected by ABO discrepancy in a patient with acute osteomyelitis has not been reported before.

Polymorphism of M341I in the Type A Human Natriuretic Peptide Receptor Gene in Essential Hypertension in Korea / 이화의대지

OBJECTIVES: There are 3 subtypes of natriuretic peptide (NP) receptors: type A natriuretic peptide receptor (NPRA), NPRB, and NPRC. The NPRA gene polymorphism, consisting of substition of methionine (ATG) to isoleucine (ATC) at nucleotide 1023 (M341I) of exon 3 was revealed to be associated with increased risk for essential hypertension (EH) in Japanese people. The purpose of this study is to investigate association between EH and the M341I polymorphism in the NPRA gene in Korea. METHODS: Eighty patients in whom type B natriuretic peptide (BNP) was measured were enrolled in this study. 66 patients had EH and 14 patients did not. The polymorphism of M341I was evaluated by multiplex genotyping polymerase chain reaction and by sequencing analysis. RESULTS: The overall distribution of alleles was not significantly different between the control and EH groups. However, the C/C homozygous genotype was found only in the EH group. In the EH group, patient carrying the C/C homozygous genotype had the trend of having higher systolic and diastolic BP levels regardless of the previous treatment, even though other laboratory markers including BNP levels had no significant differences according to the genotypes. CONCLUSION: This would be meaningful for the first identification of the M341I polymorphism in the NPRA gene and for the first suggestion of association of the EH with it in Korea.

English or Korean? / 이화의대지

No abstract available.

Review of Molecular Markers for Thyroid Cancer / 이화의대지

The incidence of thyroid cancer has been rapidly increased in Korea. Although fine needle aspiration cytology is recommended for diagnosis of cancer, there are some limitations. Patients with indeterminate or suspicious cytology category in which malignancy cannot be ruled out usually undergone a thyroidectomy, however, only 10~25% of them finally diagnosed as cancer. According to the progress in understanding molecular mechanism, some mutations or other molecular alterations have been studied for the diagnostic and prognostic markers for thyroid cancer. The majority of papillary thyroid cancers have BRAF and RAS mutations or RET/PTC rearrangement, and approximately 80% of follicular thyroid cancers harbor a RAS mutation or PAX8/PPARgamma rearrangement. These genetic alterations are mostly studied and current clinical guidelines suggested that these molecular markers may help management for patients with indeterminate cytology. In addition, recent studies demonstrated the high sensitivity and specificity of thyroid-stimulating hormone receptor mRNA in diagnosing cancer in patients with indeterminate cytology. For the detection of recurrent or residual thyroid cancer, serum thyroglobulin is the only circulating marker in clinical practice. However, it lacks sensitivity and is unreliable specifically in the presence of antibodies to thyroglobulin. Recent studies demonstrated a significant role of measuring the mRNA of thyroglobulin, thyroid peroxidase, thyroid-stimulating hormone receptor, and sodium/iodine symporter in peripheral blood for monitoring of the recurrence of thyroid cancer.

Apolipoprotein B/A1 Ratio as Risk Factor for Cerebral Ischemic Stroke / 이화의대지

OBJECTIVES: According to current knowledge, apolipoprotein B/A1 (apoB/A1) ratio is like to be risk factor in coronary artery disease. There is evidence form case-control studies that apoB/A1 ratio may be a superior to LDL and HDL cholesterol in discriminating coronary artery disease case subject from control subject. However, relationship between apoB/A1 ratio and cerebral ischemic stroke is undefined. The main object of this study is to determine whether the risk of cerebral ischemic stroke is related to levels of apoB/A1. METHODS: The study group included 643 patients (Men, 372; Women, 271) who diagnosed cerebral ischemic stroke between January 2008 to December 2010. The control groups were composed of 378 patients (Men, 139; Women, 239) who diagnosed other neurological disease. The correlation between lipid profiles and odds ratio of 10 preliminary risk factors (total cholesterol, triglyceride, LDL, HDL, apoA1, apoB, apoB/A1 ratio, non HDL, total cholesterol/HDL ratio, LDL/HDL ratio) for stroke were analyzed. RESULTS: ApoB/A1 ratio was significantly increased in case patients compared with control subjects. Multivariate logistic regression analysis identified decrease of apoB/A1 ratio (odds ratio [OR], 1.583; 95% confidence intercal [CI], 1.105~2.269) as significantly associated with stroke. Individual apoA1 (OR, 1.303; 95% CI, 0.967~1.755) and apoB (OR, 1.397; 95% CI, 0.773~2.523) were also not significantly associated with cerebral ischemic stroke. CONCLUSION: Increase of apoB/A1 ratio is associated with an increase risk of cerebral ischemic stroke. Use of apoB/A1 ratio is efficient as conventional lipids, for the identification of subjects at increased risk of stroke. So apoB/A1 ratio to standard lipid profile testing could improve the evaluation of risk factors of cerebral ischemic stroke.

Evaluation of the Screening Tests for the Diagnosis of Plasma Cell Neoplasm

BACKGROUND: Plasma cell neoplasm is diagnosed by performing bone marrow examination, serum- and urine-protein electrophoresis, and quantification of free light chains of immunoglobulins. We characterized and quantified monoclonal proteins typical of different diagnosed conditions to determine the best screening test(s). METHODS: We retrospectively reviewed diagnosis of and the characteristics of monoclonal proteins from 113 patients with monoclonal gammopathy. Monoclonal proteins were detected by agarose-gel electrophoresis and capillary electrophoresis, and if the results were ambiguous, they were confirmed by immunofixation electrophoresis. Free light chains were measured using nephelometry. RESULTS: The concentrations of monoclonal proteins in 113 patients with different conditions were as follows: multiple myeloma (MM) (67%), 2.66 (0.87-9.48) g/dL; monoclonal gammopathy of undetermined significance (MGUS) (26%), 0.62 (0.08-2.95) g/dL; lymphoma (3%), 3.65 (1.59-6.54) g/dL; Waldenstrom's macroglobulinemia (2%), 1.99 (1.08-2.90) g/dL; amyloidosis (2%), 0.61 g/dL; and POEMS syndrome (1%), 0.99 g/dL. There was a significant difference in the concentration and kappa/lambda ratio (which was based on the immunetype of the monoclonal proteins) of the monoclonal proteins in patients with MM and MGUS (P<0.001 and P=0.004, respectively). The diagnostic sensitivity of serum-protein electrophoresis, free-light-chain assay, and bone marrow analysis was 87.6%, 84.1%, and 84.5%, respectively. The sensitivity of a combination of 2 or 3 of these tests was higher at 100%. CONCLUSIONS: A combination of protein electrophoresis with immunotyping and serum free-light-chain assay may be the best screening method for detecting monoclonal proteins since its non-invasiveness.

The Future of the Ewha Medical Journal / 이화의대지

No abstract available.

Comparison of HbA(1c) Analyzers: D-10, Variant II Turbo, Cobas Integra 800, and Afinion AS100 / 대한진단검사의학회지

BACKGROUND: The purpose of this study was to evaluate the performance and agreement among HbA(1c) values measured using selected analyzers certified by the National Glycohemoglobin Standardization Program (NGSP) and standardized by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). METHODS: HbA(1c) determined using D-10 (Bio-Rad, USA), Variant II Turbo (Turbo; Bio-Rad, USA), Cobas Integra 800 (Integra; Roche, Switzerland) and Afinion AS100 (Afinion; Axis-Shield, Norway) were compared with each other. Precision and method comparisons with Deming regression were evaluated according to CLSI recommendations. We also compared the HbA(1c) values obtained with each analyzer using either IFCC or NGSP methods by correlation analysis and kappa statistics. RESULTS: The repeatability and method/device precisions of D-10 and Afinion were acceptable. The correlation coefficients of HbA(1c) were 0.986 for D-10 vs. Afinion, 0.997 for D-10 vs. Turbo, 0.988 for D-10 vs. Integra, and 0.991 for Integra vs. Afinion. The average biases of HbA(1c) Afinion (IFCC) and HbA(1c) Integra (IFCC) against HbA(1c) D-10 (NGSP) were -1.90% and -1.79%, respectively. Kappa agreement statistics for the three diabetic control group HbA(1c) values of "less than 6.5%," "6.5%-7.5%," and "greater than 7.5%" for D-10 vs. Turbo, D-10 vs. Integra, and D-10 vs. Afinion were 0.872, 0.836, and 0.833, respectively. CONCLUSIONS: The strong correlations and good clinical agreements of HbA(1c) between each analyzer expressed in terms of either NGSP or IFCC-derived NGSP indicate that these analyzers can be used interchangeably.

Immunophenotypic Features of Granulocytes, Monocytes, and Blasts in Myelodysplastic Syndromes / 대한진단검사의학회지

BACKGROUND: Despite the diagnostic utility of immunophenotyping for myelodysplastic syndromes (MDS), it has not been widely performed, and reports on this are absent in Korea. We aimed to evaluate the immunophenotypic features of non-blastic granulocytes, monocytes, and blasts in patients with MDS and non-clonal disorders using routine flow cytometry (FCM). Moreover, we evaluated the phenotypic abnormalities of mature cells in leukemic patients. METHODS: Marrow aspirates from 60 patients, including 18 with MDS, 18 with leukemia, and 24 with non-clonal disorders (control group), were analyzed using FCM. Blasts, non-blast myeloid cells, and monocytes were gated based on CD45 expression and side scatter (SSC). The phenotypes were then compared among the 3 groups. RESULTS: Compared to non-clonal disorders, the granulocytic lineages of MDS showed decreased SSC (P=0.005), increased CD45 intensity (P=0.020), decreased CD10-positive granulocytes (P= 0.030), and a higher CD56-positive rate (P=0.005). It is noteworthy that similar results were obtained in the leukemia group, and these findings were not related to the phenotypes of the leukemic cells. Using blast and monocytic gating, useful parameters for generating a differential diagnosis were not found. CONCLUSIONS: Gating the granulocytic region is a relatively easy method for MDS immunophenotyping. Among the parameters studied, SSC, CD10, and CD56 were the most useful for differentiating MDS from non-clonal disorders. While immunophenotypic changes in MDS appear to be useful for differentiating MDS from non-clonal disorders, these changes were also noted in the mature cells of leukemic patients.