Jinsook Lim

The 99th percentile values of six cardiac troponin assays established for a reference population using strict selection criteria

BACKGROUND Since the 99th percentile reference limit for cardiac troponin (Tn) can vary depending on the reference population, Sandoval et al. published systematic selection criteria. In this study, these systematic criteria were applied for the first time to obtain the 99th percentile reference limits for 6 Tn tests. METHODS The reference population was selected in accordance with the systematic criteria, and reference limits were set with respect to the six types of Tn assays. The coefficient of variation (CV) at the reference limit was determined using 3-4 concentrations of frozen serum. RESULTS In total, 641 South Koreans (303 males, 338 females) were selected as the reference population. The 99th percentile reference limit of Tn in the six assays ranged from 13.4 to 34.2pg/ml. The measurable fractions among the reference population ranged from 1.3% to 80.5%. The CVs at the reference limit ranged from 5.3% to 43.0%, and three were <10%. CONCLUSIONS In this study, a reference population was selected for the first time in accordance with the systematic criteria of Sandoval et al., and the reference limit for South Koreans was established. The values obtained in this study are different from those proposed by manufacturers, which confirms the importance of having a reference population. Four out of six assays did not fulfill the criteria for high-sensitivity tests.

A case of acute promyelocytic leukemia concomitant with plasma cell myeloma.

Dear Editor AML is a myeloid clonal malignancy characterized by the accumulation of abnormal immature myeloid cells in the bone marrow. The occurrence of therapy-related AML as a late complication of cytotoxic therapy is well documented [1], and several regimens for the treatment of plasma cell myeloma (PCM) have been associated with the development of myeloid neoplasms, such as AML, myelodysplastic syndrome, and myeloproliferative neoplasm [2]. The simultaneous occurrence of AML with various plasma cell dyscrasias without prior exposure to chemotherapy or radiotherapy is extremely rare, and most reported cases are of the myelomonocytic or monocytic subtype [3-6]. Herein, we report the first case of simultaneous acute promyelocytic leukemia (APL) and PCM presentation without previous exposure to chemotherapy or radiotherapy. A 60-yr-old man with a history of diabetic nephropathy, hypertension, and acute myocardial infarction with subsequent congestive heart failure presented to the emergency department with a 1-week history of general weakness, poor oral intake, and nausea. Neither hepatomegaly nor splenomegaly was detected on physical examination. The initial complete blood counts were the following: hemoglobin (11.5 g/dL, reference range: 13.5-17.4 g/dL), white blood cell count (2.7×109/L, reference range: 3.8-10.0×109/L), platelet count (378×109/L, reference range: 130-400×109/L), and white blood cell differential indicated 1% band neutrophils; 29% neutrophils; 62% lymphocytes; 2% monocytes; 4% eosinophils; and 2% basophils. Initial biochemical tests determined levels of total protein, (7.1 g/dL, reference range: 6.5-8.0 g/dL), albumin (2.9 g/dL, reference range: 4.0-5.0 g/dL), creatinine (5.1 mg/dL, reference range: 0.8-1.2 mg/dL), total calcium (6.6 mg/dL, reference range: 8.7-10.6 mg/dL), phosphorus (4.8 mg/dL, reference range: 2.5-4.7 mg/dL), β2 microglobulin (9.29 mg/L, reference range: 0-3.0 mg/L), and serum IgG (3,018 mg/dL, reference range: 680-1,620 mg/dL). Capillary electrophoresis (Sebia, Norcross, GA, USA) of serum and urine proteins showed a monoclonal peak (1.41 g/dL, 21.1% in serum; 0.22 g/dL, 8.3% in urine) in the gamma-globulin region, and immunofixation electrophoresis confirmed monoclonal gammopathy of IgG, kappa type. The ratios of serum and urine kappa/lambda light chains were 1.69 (reference range: 0.26-1.65) and 5.33 (reference range: 0.26-1.65), respectively. Radiologically, no osteolytic lesions were detected, but spinal magnetic resonance imaging (MRI) showed abnormal bone marrow signal intensity related to PCM. A bone marrow aspirate was composed of 10% myeloblasts, 23% abnormal hypergranular promyelocytes containing Auer rods, and 16% plasma cells. Myeloblasts and abnormal promyelocytes stained strongly positive for myeloperoxidase (MPO). The cellularity of biopsy was 70% and diffuse infiltration of two distinct populations consisting of leukemic myeloid cells (myeloblasts and abnormal promyelocytes) and plasma cells was observed. Immunohistochemical staining of the marrow biopsy showed significant positivity for CD138 and kappa light chain (Fig. 1). Flow cytometric analysis demonstrated blastic cells expressing CD13, CD33, and cytoplasmic MPO, but not HLA-DR, CD34, or CD15, consistent with the characteristics of APL. Cytogenetic analysis revealed a karyotype of 46,XY,t(15;17)(q22;q21)[4]/46,XY[16], and FISH confirmed nuc ish (PML,RARA)x3(PML con RARAx2)[64/200]. Nested reverse transcriptase-polymerase chain reaction (Seegene, Seoul, Korea) determined rearrangement of the PML/RARA gene. On the basis of these findings, we diagnosed the patient with APL concomitant with PCM, and the patient was initially treated with all-trans retinoic acid (ATRA) for 1 week. The patient refused additional chemotherapy because of his deteriorating physical condition after administration of ATRA and was discharged after 4 months of supportive care. Fig. 1 (A) Bone marrow aspiration showing abnormal promyelocytes (yellow arrow), Faggot cells (black arrow), and plasma cells (red arrow) (Wright stain, ×1,000) and (B) Immunohistochemical stain with CD138, (left, ×100), kappa light chain (middle, ... AML and PCM are different disease entities, and most concomitant cases result from leukemia that develops because of chemotherapy for preceding myeloma. Undiagnosed or untreated PCM co-presenting with AML is rare, with only 13 reports in the literature to date [7-9]. To our knowledge, this is the first reported case of APL concomitant with PCM worldwide. In this case, the diagnosis of APL was evident because of the presence of abnormal promyelocytes, Faggot cells, and the PML/RARA gene rearrangement. Before concluding that plasmacytosis is associated with clonal hematologic malignancy or PCM, reactive plasmacytosis should be ruled out because plasmacytosis can co-occur with AML [10], in which interleukin-6 production by leukemic blasts may stimulate plasma cell growth [11]. The patients various chronic conditions confounded the assessment of CRAB (hypercalcemia, renal insufficiency, anemia, and bony lesion) to prove end-organ damage by PCM. In this case, anemia could be attributed to the underlying chronic diseases, and the decrease of albumin and elevation of creatinine levels usually accompanied by PCM were masked by diabetic nephropathy. Elevation of total protein levels was not prominent, and hypercalcemia was also not observed because of the patients nephropathy. As MRI is more sensitive than a skeletal survey, the increased signal intensity detected by MRI determined bony lesions in PCM [12]. The creatinine level in this patient was stable (3 mg/dL), but was aggravated on presentation possibly because of PCM, and urgent hemodialysis was needed. In addition, bone marrow with 16% plasma cells was noted, which is not usually seen in reactive plasmacytosis, where plasma cells typically do not exceed 10% [13]. The presence of >10% plasma cells, monoclonal gammopathy by electrophoresis, kappa restriction by immunohistochemical stain, aggravation of kidney function, and bony lesions in MRI lead to the conclusion of clonal plasmacytosis, and a final diagnosis of APL concomitant with PCM was made. The proposed reasons for concurrent presentation of 2 different hematologic malignancies are abnormal multipotent stem cells, environmental risk factors, repeated infections that result in the development of a leukemic clone, and decreased immune surveillance, which may result in failure to eliminate leukemic clones [6, 11, 14]. In cases of APL followed by chemotherapy for PCM, a regimen of ATRA or allogeneic stem cell transplantation can be considered treatment options [1, 15], but treatment regimens for concomitant malignancies are not fully established because the co-occurrence of APL and PCM is rare. In this case, treatment with ATRA was begun with the intent to add idarubicine; however, additional chemotherapy was discontinued because the patient developed sepsis with aggravated general weakness. Aside from 1 patient who received stem cell transplantation [9], there have been no reports on survival of patients with concomitant AML and PCM who received chemotherapy, and the time interval from diagnosis to death in most cases was <5 months. The prognosis of this patient was poor because of his deteriorating condition despite appropriate supportive care. In conclusion, we described the first case of concomitant APL and PCM, suggesting that 2 distinct diseases can present coin cidentally without previous chemotherapy. Although rare, plasmacytosis can occur in AML, and clonality should be ruled out because of the simultaneous presentation of these 2 different hematological malignancies.

The prognostic impact of lymphocyte subsets in newly diagnosed acute myeloid leukemia

Background Tumor-infiltrating lymphocytes, which form a part of the host immune system, affect the development and progression of cancer. This study investigated whether subsets of lymphocytes reflecting host-tumor immunologic interactions are related to the prognosis of patients with acute myeloid leukemia (AML). Methods Lymphocyte subsets in the peripheral blood of 88 patients who were newly diagnosed with AML were analyzed by quantitative flow cytometry. The relationships of lymphocyte subsets with AML subtypes, genetic risk, and clinical courses were analyzed. Results The percentages of T and NK cells differed between patients with acute promyelocytic leukemia (APL) and those with AML with myelodysplasia-related changes. In non-APL, a high proportion of NK cells (>16.6%) was associated with a higher rate of death before remission (P=0.0438), whereas a low proportion of NK cells (≤9.4%) was associated with higher rates of adverse genetic abnormalities (P=0.0244) and relapse (P=0.0567). A multivariate analysis showed that the lymphocyte subsets were not independent predictors of survival. Conclusion Lymphocyte subsets at diagnosis differ between patients with different specific subtypes of AML. A low proportion of NK cells is associated with adverse genetic abnormalities, whereas a high proportion is related to death before remission. However, the proportion of NK cells may not show independent correlations with survival.

Cohort Study of Pulmonary Tuberculosis (COSMOTB) identifying drug-resistant mutations: protocol for a prospective observational study in Korea

Introduction Drug-resistant tuberculosis (TB) is a global concern. The proper diagnosis and management of drug-resistant TB are critical for improving treatment outcome. Molecular-based genotypic drug-susceptibility testing (DST) was developed to identify drug-resistant TB; however, discordant results from phenotypic and genotypic DST analyses have alarmed clinicians and raised concerns about the test’s utility. Moreover, the characteristics of disputed mutations are not well studied and only based on retrospective study findings. Methods and analysis We describe a 28-month prospective observational cohort study ongoing at two university-affiliated hospitals in South Korea. The cohort study will enrol and evaluate 600 adults with pulmonary TB. Relevant clinical and epidemiological data will be collected prospectively and participants will be evaluated at each hospital during anti-TB treatment to identify factors associated with TB treatment outcomes. Respiratory specimens will be collected at select visits. After generating a well-characterised cohort, patterns of drug resistance on both phenotypic and genotypic DSTs and associated mutations including the disputed mutation will be evaluated. We will also identify various clinical and socioeconomic factors that affect the causes of drug resistance and their clinical outcomes. Ethics and dissemination The study protocol is approved by the Institutional Review Boards of Chungbuk National University Hospital and Chungnam National University Hospital. Study results will be disseminated through peer-reviewed journals and conference presentations. Trial registration number KCT0002594.

Evaluation of the LABGEO PT10 Point-Of-Care Testing Device: Comparison of Analyte Measurements in Capillary Whole Blood and Lithium Heparin Whole Blood Samples With Those in Central Laboratory

Point‐of‐care (POC) testing device has been widely used because of its rapid availability of results making diagnosis and management as early as possible. Capillary blood can reduce the difficulty of obtaining samples compared to venous blood and allows the prompt testing results. In this study, we evaluated the usefulness of capillary blood in Samsung LABGEO PT10.

Fully international system of units-traceable glycated hemoglobin quantification using two stages of isotope-dilution high-performance liquid chromatography–tandem mass spectrometry

Glycated hemoglobin (HbA1c), defined as hemoglobin (Hb) molecules having a stable adduct of glucose on the N-terminal of the β-chains, has been endorsed as a diagnostic tool for diabetes mellitus and a prediction indicator for the development of diabetes complications. Here we describe an accurate procedure using two stages of isotope dilution-ultra performance liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) for the quantification of HbA1c that provides full traceability to International System of Units (SI). First, synthetic peptides representing specific markers of HbA1c (G-hexa) and hemoglobin A0 (Hexa) were certified by amino acid analysis via acid hydrolysis as reference materials (RMs) for the next step. For this peptide certification, three amino acids (proline, valine, and leucine) were determined by hydrolysis with 10M hydrochloric acid at 130°C for 48h followed by ID-LC-MS/MS. Then, HbA1c content in blood was quantified with the ratio of specific proteolytic peptides from HbA1c and HbA0 via enzyme digestion using ID-LC-MS/MS with the certified peptides as RMs and isotope-labeled peptides as internal standards. Results demonstrate complete traceability to SI-units throughout this procedure. Reliability was confirmed through comparative studies with commercially available RMs for HbA1c, and other routine HbA1c diagnostic methods as well. Following full method validation, we applied this procedure to the certification of candidate hemolysate-certified RMs for HbA1c content, as well as 52 real clinical samples. All of the results showed the suitability of this method to act as a primary reference measurement procedure for HbA1c in complex biological samples.

Evaluation of an Automated Reader and Color Interpretation-Based Immunoassays for Multiplexed Drug-of-Abuse Testing in Urine

On-site drugs of abuse testing devices have undergone continuous improvement. We evaluated three devices with different designs: an automated reader, the Multi-Drug Screen Test Device with DxLINK (DxLINK; Innovacon, Alere, San Diego, USA) and two colorimetric immunoassays, the One Step Multi-Line Screen Panel with Integrated E-Z Split Key Cup II (E-Z Cup; Innovacon, Alere) and the One Step Multi-Drug Screen Panel card (Multi4 card; Alere, Abon Biopharm, Hangzhou, China). Eleven drugs [amphetamine, secobarbital, oxazepam, buprenorphine, benzoylecgonine, methylenedioxymethamphetamine (MDMA), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC), methamphetamine, methadone, morphine and nortriptyline] were tested using the DxLINK and E-Z Cup. Four drugs (benzoylecgonine, THC, methamphetamine and morphine) were tested using the Multi4 card using control materials (Detectabuse Stat-Skreen; Biochemical Diagnostics, Edgewood, NY, USA). The concentrations (-50%, -25%, +25%, +50% and 3× cut-off values) of the control materials were confirmed by mass spectrometry. Concordance rates were calculated around cut-offs. All devices showed high overall agreement rates of >90% with a few exceptions: the DxLINK exhibited lower sensitivity for benzoylecgonine, methadone and nortriptyline (60% and 30%, 92% and 40%, and 96% and 60% sensitivity at +50% and +25% cut-off levels, respectively). The E-Z Cup exhibited lower sensitivity for oxazepam and nortriptyline (97% and 50%, and 97% and 40% sensitivity at +50% and +25% cut-off levels, respectively). We additionally evaluated test-band color by visual inspection using a standard color-scale card. When detailed color criteria for determination of positivity were applied for the E-Z Cup, using slightly less stringent criteria, oxazepam, buprenorphine, MDMA and nortriptyline showed increases in sensitivity from 70-80% to 90-100%, all with a specificity above 98%. Overall, all devices exhibited satisfactory performance at ±50% cut-off levels for commonly used drugs, with the exception of lower sensitivity for cocaine testing for DxLINK. Careful evaluation of devices and elaborate calibration of visual interpretation for determining positivity may help improve the performance of these devices.