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Analytical Characteristics of High-Sensitivity Cardiac Troponin Assays.

Laboratory Medicine Online.2014;4(1):55-62. doi:10.3343/lmo.2014.4.1.55

BACKGROUND: Cardiac troponins I (cTnI) and T (cTnT) have received international endorsement as the standard biomarkers for detection of myocardial injury, for risk stratification in patients suspected of acute coronary syndrome, and for the diagnosis of myocardial infarction. An evidence-based clinical database is growing rapidly for high-sensitivity (hs) troponin assays. Thus, clarifications of the analytical principles for the immunoassays used in clinical practice are important. CONTENT: The purpose of this mini-review is (a) to provide a background for the biochemistry of cTnT and cTnI and (b) to address the following analytical questions for both hs cTnI and cTnT assays: (i) How does an assay become designated hs? (ii) How does one realistically define healthy (normal) reference populations for determining the 99th percentile? (iii) What is the usual biological variation of these analytes? (iv) What assay imprecision characteristics are acceptable? (v) Will standardization of cardiac troponin assays be attainable? SUMMARY: This review raises important points regarding cTnI and cTnT assays and their reference limits and specifically addresses hs assays used to measure low concentrations (nanograms per liter or picograms per milliliter). Recommendations are made to help clarify the nomenclature. The review also identifies further challenges for the evolving science of cardiac troponin measurement. It is hoped that with the introduction of these concepts, both laboratorians and clinicians can develop a more unified view of how these assays are used worldwide in clinical practice.
Acute Coronary Syndrome ; Biochemistry ; Biomarkers ; Diagnosis ; Hope ; Humans ; Immunoassay ; Myocardial Infarction ; Troponin*

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A Case of Catheter-related Kocuria marina Bloodstream Infection in a Patient with Multiple Myeloma.

Mi Na LEE ; Hee Jae HUH ; Borham KIM ; Cheol In KANG ; Kihyun KIM ; Chang Seok KI ; Nam Yong LEE

Laboratory Medicine Online.2014;4(1):51-54. doi:10.3343/lmo.2014.4.1.51

Kocuria species are gram-positive cocci that are commonly found on human skin, mucosa, and oropharynx. They can cause opportunistic infections in patients with underlying disease or intravenous catheterization. Although several cases of bacteremia caused by Kocuria rosea, Kocuria kristinae, and Kocuria rhizophila have been documented, K. marina has not been reported as a bloodstream pathogen. We isolated K. marina from the blood of a patient with multiple myeloma as a cause of catheter-related bacteremia. The VITEK II system (bioMerieux, Inc.) identified the isolate as K. variance. However, 16S rRNA gene sequencing analysis identified the isolate as K. marina. Accurate identification of Kocuria to the species level requires molecular methods that precisely identify these rare pathogens.
Bacteremia ; Catheter-Related Infections ; Catheterization ; Catheters ; Genes, rRNA ; Gram-Positive Cocci ; Humans ; Methods ; Mucous Membrane ; Multiple Myeloma* ; Opportunistic Infections ; Oropharynx ; Skin

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Performance Comparison of ImmunoCAP and HYTEC 288 in the Quantitative Tests of Allergen-specific IgE.

Seung Hee LEE ; Sun Min LEE ; Hyung Hoi KIM ; Chulhun L. CHANG ; Eun Yup LEE

Laboratory Medicine Online.2014;4(1):43-50. doi:10.3343/lmo.2014.4.1.43

BACKGROUND: In vitro measurement of allergen-specific IgE has become an important part of allergy diagnoses. HYTEC 288 system (Hycor Biomedical Inc., USA), which was recently introduced in Korea, is a fully automated immunoassay for quantitative measurements of allergen-specific IgE. In this study, we compared the clinical utility of this in vitro allergy test with that of ImmunoCAP assay (ImmunoDiagnostics, Sweden). METHODS: To evaluate the reproducibility of HYTEC 288 system, 50 serum samples were tested in duplicate each for Dermatophagoides pteronyssinus (d1) and D. farinae (d2) specific IgE. To assess the agreement between ImmunoCAP and HYTEC 288 assays, 56 serum samples were tested for the other 21 allergen-specific IgE. RESULTS: No significant differences within the range of quantitative analysis were observed between HYTEC 288 and ImmunoCAP assays for d1 and d2 (P=0.65 and 0.55, respectively). The agreements of HYTEC allergen-specific IgE assay with ImmunoCAP within +/-1 class grade were 80% and 100% for d1 and d2, respectively. The correlation coefficients between HYTEC 288 and ImmunoCAP results within the range of quantitative analysis were overally 0.90, regardless of allergen, for d1 and d2 specific IgE, 0.91 and 0.98, respectively. Running times for the HYTEC 288 and Phardia 100 were 5.5 and 4.6 min per test, respectively. CONCLUSIONS: Hycor HYTEC 288 showed a favorable agreement with ImmunoCAP and can be used for fully automated quantitative measurements of allergen-specific IgE in the clinical laboratory.
Automation ; Dermatophagoides pteronyssinus ; Diagnosis ; Hypersensitivity ; Immunoassay ; Immunoglobulin E* ; Korea ; Running

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Establishment and Multicenter Evaluation of a National Reference Panel for Syphilis Antibodies in Korea.

Hee Jin HUH ; Seok Lae CHAE ; Deok Ja OH ; Quehn PARK ; Chae Seung LIM ; Tae Hyun UM ; Yun Mi PARK ; Young Joo CHA

Laboratory Medicine Online.2014;4(1):36-42. doi:10.3343/lmo.2014.4.1.36

BACKGROUND: Establishment of a national reference panel for syphilis antibodies is necessary to evaluate the performance of in-vitro diagnostic tests for syphilis and to verify test quality. This study aimed to establish a national reference panel for syphilis antibodies, to assess the suitability of a panel for non-treponemal and treponemal testing, and to assess the reactivity of the various tests currently in use. METHODS: Treponemal pallidum particle agglutination (TPPA)-positive and -negative fresh frozen plasma samples were obtained. After the fresh frozen plasma was converted to serum by defibrination, the samples were pooled. Two candidate reference standards containing no syphilis antibodies and 10 candidate reference standards containing syphilis antibodies were prepared on the basis of reactivity in the TPPA assay. Candidate reference standards were tested by three laboratories using five non-treponemal tests and four treponemal tests. RESULTS: All three laboratories reported positive non-treponemal test results for the mixed-titer performance panel (MP)/6-MP/12. MP/1, MP/2, and MP/3 were negative for non-treponemal tests. MP/4 and MP/5 were reported either as positive or negative according to the laboratories. All laboratories reported positive TPPA results for MP/3-MP/12 and negative results for MP/1 and MP/2. No significant difference was detected among the treponemal testing results in three laboratories. CONCLUSIONS: We established 12 candidate national reference standards containing various concentrations of syphilis antibodies. A collaborative study using nine tests demonstrated that 12 candidate national reference standards presented consistent results, except a few assays with low sensitivity, and thus could be used as a national reference panel for syphilis antibody testing.
Agglutination ; Antibodies* ; Diagnostic Tests, Routine ; Korea* ; Plasma ; Syphilis*

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Direct Measurement of Serum Immunoglobulin Heavy and Light Chain Pairs for Identification of Monoclonal Gammopathy and a Performance Comparison with Capillary Electrophoresis.

Min Gu KANG ; Myung Geun SHIN ; Jin Gak KIM ; Min Joong JANG ; O Jin LEE ; Hye Ran KIM ; Duck CHO ; Soo Hyun KIM ; Seung Jung KEE ; Jong Hee SHIN ; Soon Pal SUH ; Dong Wook RYANG

Laboratory Medicine Online.2014;4(1):28-35. doi:10.3343/lmo.2014.4.1.28

BACKGROUND: Determination of monoclonal gammopathy through conventional protein electrophoresis is sometimes difficult because of the presence of large proteins such as haptoglobin and transferrin, which may obscure the results. Ambiguity in an electrophoresis band can give rise to confusion or difficulty in interpretation. The heavy chain/light chain assay (HLC assay) using Hevylite antibody (The Binding Site, UK) has recently been developed for the accurate measurement of monoclonal proteins. We compared the immunotyping (IT) profiles to the immunoglobulin (Ig) heavy/light chain measurements obtained using the HLC assay and observed the ratios between intact Ig kappa and lambda. METHODS: We collected 35 and 28 sera from patients with suspicious and definitive monoclonal protein, respectively. Then we performed serum protein electrophoresis (SPEP) and IT by Capillarys2 (Sebia, USA). Monoclonal protein production was investigated using Freelite antibody (The Binding Site) and specific Ig(G, A)kappa and Ig(G, A)lambda Hevylite antibodies. The results were analyzed using PASW 18.0 for Windows (IBM, USA). RESULTS: Direct measurement of Ig heavy/light chains showed discordant IT results for 12 (34.2%) of 35 patients' sera with suspicious SPEP pattern and identical IT results for 28 patients' sera with definitive monoclonal peak in the SPEP results. Overall, the results of the HLC assay and IT showed good agreement (kappa=0.718, P=0.000 by cross-tabulation Gamma, Kappa analysis). CONCLUSIONS: The results of direct measurement of serum Ig heavy chain/light chain pairs were comparable to those of IT and were helpful for determination of monoclonality in the case of ambiguous electrophoresis results. Measurement of the heavy chain/light chain pair ratio also allowed precise quantification of the monoclonal Igs with ambiguous electrophoresis patterns and identification or discrimination of clonality.
Antibodies ; Binding Sites ; Capillaries* ; Discrimination (Psychology) ; Electrophoresis ; Electrophoresis, Capillary* ; Haptoglobins ; Humans ; Immunoglobulins* ; Multiple Myeloma ; Paraproteinemias* ; Transferrin

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Evaluation of the T-KB-H and 3-HB Kits for the Measurement of Serum Ketone and beta-Hydroxybutyric Acid.

Kyunghoon LEE ; Sun Hee JUN ; Kwang Woo LEE ; Minje HAN ; Sang Hoon SONG ; Kyoung Un PARK ; Junghan SONG

Laboratory Medicine Online.2014;4(1):22-27. doi:10.3343/lmo.2014.4.1.22

BACKGROUND: Diabetes mellitus and alcohol consumption are the most common causes of ketoacidosis in adults. Recently, beta-hydroxybutyric acid (betaHBA) was reported to be a potential serum biomarker in the diagnosis and monitoring of ketoacidosis. We evaluated the performance of T-KB-H and 3-HB kits for the measurement of ketone bodies [acetoacetate (AcAc)+betaHBA] and betaHBA, respectively. METHODS: Quantitative enzymatic assays were performed using the T-KB-H and 3-HB kits (Nittobo Medical Co., Japan) and the Architect ci16200 Integrated System (Abbott Laboratories, USA). Simultaneously, the ketone body levels in these serum samples were determined by gas chromatography-mas spectrometry (GC-MS). We evaluated precision and linearity of these kits and correlation with GC-MS, and established reference intervals in children and adults. RESULTS: The coefficients of variation for the T-KB-H and 3-HB kits were less than 4.0% at analyte levels of 50, 100, and 400 micromol/L. Linearity was observed for AcAc and betaHBA over a 0-1,000 micromol/L range (R2<0.99). Results from the T-KB-H and 3-HB kits were in good agreement with those from the GC-MS analysis, with correlation coefficients of 0.94 for AcAc and 0.96 for betaHBA. Reference intervals determined for the T-KB-H kit were 9.8-270.1 micromol/L and 18.5-531.8 micromol/L in children and adults, respectively. For the 3-HB kit, the reference intervals were 6.4-234.0 micromol/L and 16.0-437.2 micromol/L in children and adults, respectively. CONCLUSIONS: The T-KB-H and 3-HB kits displayed good precision, clinically acceptable linearity, and reliable correlation with an established assay. This indicates that the kits can be used clinically for measuring serum ketone bodies.
3-Hydroxybutyric Acid* ; Adult ; Alcohol Drinking ; Child ; Diabetes Mellitus ; Diabetic Ketoacidosis ; Diagnosis ; Enzyme Assays ; Gas Chromatography-Mass Spectrometry ; Humans ; Ketone Bodies ; Ketosis ; Spectrum Analysis

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Evaluation of the Wisecheck Glucose Monitoring System.

Seonhee KWON ; Ha Nui KIM ; Sun Young KO ; Chi Hyun CHO ; Jang Su KIM ; Chae Seung LIM

Laboratory Medicine Online.2014;4(1):15-21. doi:10.3343/lmo.2014.4.1.15

BACKGROUND: Glucometers are widely used for self-monitoring and point-of-care testing in diabetes management. We evaluated the performance of the recently developed Wisecheck Glucose Monitoring System (Wisemeditech, Korea) compared to that of 2 other well-known glucometer systems. METHODS: The Wisecheck glucometer was evaluated for precision, linearity, and carryover rate. One-hundred fifty samples samples were tested, and the results obtained from the Wisecheck glucometer, ACCU-CHEK Performa (Roche Diagnostics, Germany) and SD GlucoLink (SD Diagnostics, Korea) were compared to those obtained using the laboratory reference method from the Toshiba 200FR (Toshiba, Japan), according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: The coefficient of variation (CV) values for within-run imprecision at low, middle, and high levels were 2.06%, 1.02%, and 2.02%, respectively, and the CV values for total-run imprecision at low, middle, and high levels were 2.98%, 2.41%, and 1.88%, respectively. In the linearity test, the coefficient of determination (R2) was 0.9985 in glucose concentration ranging from 48.6 mg/dL to 428 mg/dL (P<0.0001). The results obtained using the Wisecheck glucometer were well correlated with those obtained using the Toshiba 200FR (R2=0.980, P<0.0001). The carryover rate was 0.12%. CONCLUSIONS: The Wisecheck glucometer showed good precision, linearity, and correlation with the reference method. It provided rapid and reliable measurements of blood glucose levels and seemed appropriate for use in diabetes management.
Blood Glucose ; Diabetes Mellitus ; Glucose* ; Methods

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Mobilization of Peripheral Blood Stem Cells for Autologous Transplantation in Patients with Hematologic Malignancies.

Min Ji KIM ; Sang Gyung KIM ; A Jin LEE ; Hae Bong JANG ; Seong Hwa BAE ; Hyun Mo RYU

Laboratory Medicine Online.2014;4(1):8-14. doi:10.3343/lmo.2014.4.1.8

BACKGROUND: Autologous peripheral blood-stem cell transplantation (autoPBSCT) is the treatment of choice for hematologic malignancy, because the technique requires neither general anesthesia nor surgical intervention, amongst many other advantages. Despite these benefits, the risk of hematologic malignancy, as well as the effect of patient age and sex on the prediction of successful collection of autoPBSCT are still unclear. The purpose of this study was to examine whether the hematologic diagnosis of the disease, and age or sex affect the mobilization of CD34+ cells and mononuclear cells. METHODS: We retrospectively investigated 30 (6 multiple myeloma, 11 diffuse large B-cell lymphoma, 8 acute myeloid leukemia, 2 acute lymphoid leukemia, and 3 T-cell lymphoma) patients who underwent autoPBSCT between 2008 and 2011 at Daegu Catholic University Hospital. RESULTS: Patients with multiple myeloma had the highest average of both mononuclear cell (MNC) (2.07+/-0.67x10(8) cells/kg) and CD34+ cell (1.28+/-0.58x10(6) cells/kg) counts. Patients with T-cell lymphoma had both the lowest MNC (1.23+/-0.49x10(8) cells/kg) and CD34+ cell (0.20+/-0.6x10(6) cells/kg) counts. Male patients showed greater collected CD34+ cell counts (0.96+/-1.38x10(6) cells/kg) and MNC counts (1.71+/-0.76x10(8) cells/kg) than the female patients. Patients under the age of 44 had higher collected CD34+ cell counts (0.96+/-1.37x10(6) cells/kg) but lower counts of MNC (1.49+/-0.74x10(8) cells/kg). CONCLUSIONS: The collected MNC and CD34+ cell counts varied between the types of malignancies, and with respect to sex and age. However, only collected MNC counts were significantly different (P<0.05) among the different types of malignancies.
Anesthesia, General ; Autografts* ; Cell Count ; Cell Transplantation ; Daegu ; Diagnosis ; Female ; Hematologic Neoplasms* ; Humans ; Leukemia, Myeloid, Acute ; Lymphoma, B-Cell ; Lymphoma, T-Cell ; Male ; Multiple Myeloma ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; Retrospective Studies ; Stem Cells* ; T-Lymphocytes ; Transplantation, Autologous* ; Transplants

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Assessment of Cell Viability in Umbilical Cord Blood by Using 7-AAD/annexin V Dual Staining.

Kyeong Mi KIM ; Ji Young HUH ; Myung Seo KANG ; Sang Hee JUNG

Laboratory Medicine Online.2014;4(1):1-7. doi:10.3343/lmo.2014.4.1.1

BACKGROUND: The quality of cord blood largely depends on cell viability. Viability assessments using trypan blue or 7-aminoactinomycin (7-AAD) staining, which are commonly used methods, may not reflect early apoptosis of cord blood cells. We aimed to investigate early apoptosis in cord blood cells following elapsed time after collection using double staining with annexin V and 7-AAD and to compare the result with that of viability evaluation using trypan blue or 7-AAD staining. METHODS: Umbilical cord blood samples were obtained from 30 pregnant women at the time of delivery between July 2012 and March 2013. Viability of cord blood cells was determined at 0 (T0), 24, and 48 hr after collection by using trypan blue exclusion assay, 7-AAD staining, and 7-AAD/annexin V staining. RESULTS: Viabilities defined by 7-AAD/annexin V staining at T0, 24, and 48 hr after collection were respectively as follows: total nucleated cells, 92.8+/-4.5%, 78.4+/-7.8%, and 65.5+/-8.1%; mononuclear cells, 94.4+/-1.7%, 90.8+/-4.2%, and 84.2+/-6.7%; and CD34-positive cells, 92.4+/-3.0%, 90.7+/-4.7%, and 89.3+/-7.0%. The viability using trypan blue was more than 90% until 48 hr after collection. CONCLUSIONS: The mean viability of total nucleated cells using 7-AAD/annexin V staining decreased to less than 80% at 24 hr after collection; however, the viability of CD34-positive cells was more than 85% until 48 hr. Our study's data will provide useful information for the assessing the quality of cord blood products.
Annexin A5 ; Apoptosis ; Cell Survival* ; Female ; Fetal Blood* ; Humans ; Methods ; Pregnant Women ; Trypan Blue ; Umbilical Cord*

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Antibiotic Resistance: How Serious Is the Problem, and What Can Be Done?.

Alexander J MCADAM ; David C HOOPER ; Alfred DEMARIA ; Brandi M LIMBAGO ; Thomas F O'BRIEN ; Betsy MCCAUGHEY

Laboratory Medicine Online.2013;3(2):124-127. doi:10.3343/lmo.2013.3.2.124

No abstract available.

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