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Analysis of the Patients with Indeterminate Results by Anti-HIV Western Blot Assay: Experience of a University Hospital During Recent 5 Years in Korea.

Eun Young LEE ; Jonghyeon CHOI ; Yongjung PARK ; Jong Han LEE ; Hyon Suk KIM

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):49-55.

BACKGROUND: Interpretation of indeterminate results by anti-HIV Western blot assay, which is currently used as a confirmatory test for HIV infection, can be usually difficult. We analyzed outcomes of the patients with indeterminate results by anti-HIV Western blot. METHODS: Medical records of patients, who were indeterminate by the anti-HIV Western blot assay in a university hospital during recent 5 years, were retrospectively reviewed. HIV screening test was performed by chemiluminescent immunoassay autoanalyzer (Abbot Laboratories, USA) with HIV Ag/Ab Combo kits. Confirmatory Western blot assay for the positive samples by HIV screening test was committed to the Korean National Institute of Health. RESULTS: A total of 202,639 specimens were tested for HIV screening during the period, and 644 (0.32%) sera showed positive results. Among these, 46 (7.1%) cases were indeterminate by the Western blot, which were from 20 patients, and 13 of them converted to be anti-HIV positive, and 3 were lost to follow-up. Another four patients were turned out to be negative for HIV infection, including two neonates from HIV-positive mothers receiving antiviral treatment during pregnancy. CONCLUSIONS: Most of the patients who showed Western blot-indeterminate results converted to HIV positive after follow-up. Thus, careful monitoring of patients with indeterminate Western blot results should be essential.
Blotting, Western ; Follow-Up Studies ; HIV ; HIV Infections ; Humans ; Immunoassay ; Infant, Newborn ; Korea ; Lost to Follow-Up ; Mass Screening ; Medical Records ; Mothers ; Retrospective Studies

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Evaluation of two Real-Time PCR Assays for the Detection of Chlamydia trachomatis.

Eun Young LEE ; Sinyoung KIM ; Hyon Suk KIM

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):43-47.

BACKGROUND: Chlamydia trachomatis is common etiological agent of sexual transmitted disease. We evaluated two real-time PCR assays for the detection of C. trachomatis; Cobas TaqMan CT test v2.0 (Roche Diagnostics, Switzerland) and AdvanSure CT/NG real-time PCR (LG Life Sciences, Korea). And we compared performance of two real-time PCR assays with Cobas Amplicor CT test (Roche Diagnostics, Switzerland). METHODS: Seventy-nine cervical swab specimens collected from patients with suspected C. trachomatis infection were tested using CTM CT, ADVANSURE, and AMPLICOR for the detection of C. trachomatis. RESULTS: Twenty-five (31.6%) samples showed positive results in all three assays. The positive and negative concordance rates among three assays were 100%. CONCLUSIONS: CTM CT and ADVANSURE showed excellent agreement with AMPLICOR. Therefore, these assays were reliable for the evaluation of C. trachomatis infection.
Biological Science Disciplines ; Chlamydia ; Chlamydia trachomatis ; Humans ; Real-Time Polymerase Chain Reaction

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Use of Immunochromatographic Assays for Identification of Mycobacterium tuberculosis Complex from Broth Cultures.

Young Kyung LEE ; Han Sung KIM ; Wonkeun SONG ; Jae Seok KIM ; Hee Jung KANG ; Kyu Man LEE

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):39-42.

BACKGROUND: Broth cultures are increasingly used to detect acid-fast bacilli (AFB). Rapid, simple and accurate methods for differentiation of Mycobacterium tuberculosis complex (MTBC) and nontuberculosis mycobacteria from broth cultures are needed. Immunochromatographic assays (ICTs) for identification of MTBC have been developed. METHODS: The abilities of the BD MGIT TBc Identification Test (Becton Dickinson, USA) and the SD Bioline TB Ag MPT64 (Standard Diagnostics, Korea) to detect MTBC were evaluated in 44 AFB-positive broth cultures. The results of 2 ICTs were compared to those of real-time PCR. RESULTS: The BD MGIT TBc Identification Test and the SD Bioline TB Ag MPT64 showed concordant results with real-time PCR by 100% and 97.7%, respectively. The sensitivity of the BD MGIT TBc Identification and the SD Bioline TB Ag MPT64 was 100% for both, and the specificities of those were 100% and 95.2%, respectively. CONCLUSIONS: Both ICTs are rapid methods for identification of MTBC from broth cultures, and the results of ICTs are in accord with those of real-time PCR.
Immunochromatography ; Mycobacterium ; Mycobacterium tuberculosis ; Real-Time Polymerase Chain Reaction

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Detection of Varicella-Zoster Virus (VZV) by Nested Polymerase Chain Reaction.

Hyoung nam LEE ; Tae eun KIM ; Hyeonju BAK ; Hyun Im LEE ; Eun Sun JUNG ; Yeong Jin CHOI

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):31-37.

BACKGROUND: Polymerase chain reaction (PCR) is known as a sensitive and specific method for the detection of varicella-zoster virus (VZV). Nested PCR is reliably used than conventional PCR to increase the sensitivity and specificity, especially in cases of small sized tissue samples. METHODS: We detected VZV infection in tissues from 111 patients using conventional PCR and nested PCR. Ninety-one cases of fresh tissues and twenty cases of formalin-fixed paraffin-embedded (FFPE) tissues were evaluated. The column method or home made lysis buffer method was used for the DNA extraction of fresh tissues and FFPE tissues. RESULTS: Among total 111 cases, VZV were detected in 62 (55.9%) cases by conventional PCR and 79 (71.2%) cases by nested PCR. The detection rate of nested PCR was higher than conventional PCR (1.27 folds). In 91 cases of fresh tissues, 56 (61.5%) were positive by conventional PCR and 68 (74.7%) by nested PCR. In 20 cases of FFPE tissues, 6 (30%) were positive by conventional PCR and 11 (55%) by nested PCR. The detection rate of VZV was increased by nested PCR both in fresh tissues (1.21 folds) and FFPE tissues (1.83 folds). CONCLUSIONS: Nested PCR is the more sensitive method than conventional PCR for the detection of VZV infection in tissues regardless of DNA extraction methods, especially for the small sized FFPE tissues.
DNA ; Herpesvirus 3, Human ; Humans ; Polymerase Chain Reaction ; Sensitivity and Specificity

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Evaluation of the i-Smart 30 Point-of-Care Analyzer for Use in Clinical Laboratory Settings.

Yoonmi SEOK ; Woonhyoung LEE ; Seoyoung YOON ; Youngchul WON ; Oh Hun KWON

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):25-30.

BACKGROUND: The i-Smart 30 point-of-care (POC) analyzer (i-SENS, Korea) is a compact and portable system used for the analysis of electrolytes (sodium, potassium, chloride) and hematocrit in whole blood samples. In this study, we evaluated the analytical performance of the i-Smart 30 analyzer. METHODS: Precision and sample-related percent carry-over were determined using the quality control materials. Comparison study was performed with the Stat Profile Critical Care Xpress (STP CCX; Nova Biomedical, USA) analyzer using venous whole blood samples. RESULTS: In the precision study, imprecision studies demonstrated within-run and total-run coefficients of variation within 0.5-3.9% and 0.7-4.4%, respectively, for all analytes. A good correlation was found between the i-Smart 30 analyzer and the STP CCX analyzer, except for chloride that showed high intercept. In the study of carry-over, sample-related carry-over for Na+, K+, Cl- and Hct were demonstrated as 0.84%, 0%, 0.86% and 1.56%, respectively. CONCLUSIONS: We conclude that the i-Smart 30 analyzer is suitable for routine use in clinical laboratories, especially where rapid test results are required such as emergency departments, intensive care units, and dialysis units. However, for Cl-, it is necessary that a significant correlation between this analyzer and a reference method should be demonstrated.
Critical Care ; Dialysis ; Electrolytes ; Emergencies ; Hematocrit ; Intensive Care Units ; Point-of-Care Systems ; Potassium ; Quality Control

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Evaluation of the Analytical Performance of NOVA StatStrip(R) Blood Glucometer in a Peritoneal Dialysis Setting.

Sook Hyang CHOI ; Pil Whan PARK ; Yiel Hea SEO ; Jeong Yeal AHN ; Kyung Hee KIM

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):17-24.

BACKGROUND: The use of point of care glucometer is widely established. However, the reliability of glucometer can vary according to the type of patients tested. Chemical interference with some current glucometer has been observed in patients undergoing peritoneal dialysis. StatStrip(R) (Nova Biomedical, USA) has been designed to compensate for this interference effect. So we compared the analytic performance and interference response of StatStrip(R) to two conventional glucometers. And we also evaluated the interference response with samples in patients undergoing peritoneal dialysis. METHODS: StatStrip(R) and two other glucometers were compared for linearity, imprecision, correlations with Advia 2400(TM) (Bayer Diagnostics, USA). Interference by lactate, maltose, were evaluated. Interferences in 20 samples of patients undergoing peritoneal dialysis were also evaluated. RESULTS: The coefficients of variation (CVs) of within-run precision were 1.70-3.77% and CVs of total precision were 1.98-3.99%. The linearity was R2=0.9776-0.988 (P<0.001). High correlation was found in each glucometer and the Advia 2400(TM). But all the glucometers showed a variable positive or negative bias compared with reference method. Including samples of patients undergoing peritoneal dialysis, maltose did not significantly influence the glucose concentration in StatStrip(R) and one of the conventional glucometers within 20% difference range. Lactate and hematocrit did not significantly influence the glucose concentration in all glucometers. CONCLUSIONS: StatStrip(R) shows good linearity, precision, correlation with the reference method and shows minimal interference effects. Our results indicate that StatStrip(R) also has clinical reliability when used in a peritoneal dialysis setting.
Bias (Epidemiology) ; Blood Glucose ; Glucose ; Hematocrit ; Humans ; Lactic Acid ; Maltose ; Peritoneal Dialysis

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A Serial Study of Hematologic Change in Burned Patients.

Hyun Soo KIM ; Hye Won KWON ; Hyeong Tae YANG ; Wook CHUN ; Kyu Sung SHIN ; Young Kyung LEE ; Ji Young PARK ; Hyoun Chan CHO ; Kyu Man LEE

Journal of Laboratory Medicine and Quality Assurance.2011;33(1):9-16.

BACKGROUND: Hematologic changes in burned patients show unique patterns with time after burn injury. In this study, we analyzed the changes of leukocyte count, hemoglobin concentration, and platelet count according to elapsed time and burn size. METHODS: A total of 265 burned patients were included in this retrospective study. The changes in leukocyte count, hemoglobin, and platelet count according to elapsed time were analyzed every 6 hours from immediately after burn injury until day 2, and then every 24 hours from day 3 to day 14. The differences according to burn size were also analyzed. All the results were expressed as mean+/-standard deviation. RESULTS: Leukocyte count, hemoglobin, and platelet count began to increasing immediately after burn injury, reaching the peak within 12 hours after injury, and then decreased. WBC count was lowest at days 3 to 4 and then began increasing, reaching the second peak at day 7-8. Hemoglobin level continuously decreased and remained at the level of anemia from day 4 to day 14. Platelet count was lowest at days 3-4 and then continuously increased until day 14. The wider the burn sizes were, the greater the changes in leukocyte count, hemoglobin, and platelet count, with 11-40% of the patients showing the most remarkable increase in the number of platelets after day 4. CONCLUSIONS: The leukocyte count, hemoglobin concentration and platelet count were dramatically changed within the first 72 hours after burn injury and the wider the burn sizes were, the greater these changes were. These results could be used as reference data for interpreting the results of complete blood count in burned patients.
Anemia ; Blood Cell Count ; Blood Platelets ; Burns ; Hemoglobins ; Humans ; Leukocyte Count ; Leukocytes ; Platelet Count ; Retrospective Studies

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Laboratory Evaluation of Automated Urine Analyzer ComboStick Reader 720(R) and Reagent Strip ComboStick 10.

Min Jung KWON ; Hyup Woo LEE ; Ga Yeong KIM ; Myeong Hyeon NAM ; Chang Kyu LEE ; Young Kee KIM

Journal of Laboratory Medicine and Quality Assurance.2009;31(1):215-223.

BACKGROUND: The ComboStick Reader 720(R)(DFI Co., Ltd. Korda) is a newly developed automated urine analyzer. The objective of this analysis was to evaluate the analytical performance of the Combostick Reader 720 and ComboStick 10 reagent strips and to compare the results using the Uriscan Pro II and Uriscan Gen 10 SGL strips (YD Diagnostics, Korea). METHODS: The Dipstick urinalyses were performed on a ComboStick Reader 720(R) using ComboStick 10 strips and on a Uriscan Pro II(R) using Uriscan 10 SGL strips. Precision was evaluated with commercial control materials. The sets of results were analyzed for concordance with weighted kappa values or intraclass correlation coefficients (ICCs). The microscopic urine analysis was carried out to confirm the results from both automated urine analyzers. Agreement between the dipstick methods and the microscopic method was evaluated by kappa values and the McNemar test. RESULTS: Within and between-run precisions of the ComboStick Reader 720(R) were 90.0% to 100%. A comparison of results from 1,700 urine samples using the ComboStick Reader 720(R) and Uriscan Pro II(R) revealed a very high concordance rate of > or = 91.0% on consideration of neighboring blocks for all analytes of the dipstick urinalysis. There was a good association between the microscopic method and the dipstick methods of the two automated urine analyzers. The ComboStick Reader 720(R) revealed a statistically higher degree of agreement for leukocytes. CONCLUSIONS: The ComboStick Reader 720(R) and ComboStick 10 strips showed good precisions and revealed a statistically significant agreement with the Uriscan Pro II(R) and Uriscan 10 SGL strips. For leukocytes, the ComboStick Reader 720(R) was superior to the Uriscan Pro II(R) in comparing the agreement between the microscopic and dipstick methods. The overall performance of the ComboStick Reader 720(R) and ComboStick 10 strips were satisfactory.
Leukocytes ; Reagent Strips ; Urinalysis

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Evaluation of the Blood Gas Analyzer GEM Premier 4000.

Hee Young CHUNG ; Hee Jung CHUNG ; Sail CHUN ; Woochang LEE ; Won Ki MIN

Journal of Laboratory Medicine and Quality Assurance.2009;31(1):207-214.

BACKGROUND: We evaluated the performance of the GEM Premier 4000 (Instrumentation Laboratory, USA), a new blood gas/electrolytes/co-oximetry analyzer, according to the Clinical and Laboratory Standard Institute (CLSI) guidelines. METHODS: Within-run precision, total-run precision, linearity and sample-related carryover were analyzed using quality control materials at three different concentration levels for each analytes. Correlation was compared with the routinely used NOVA CCX2 (Nova Biomedical, USA) with patients' whole blood samples. RESULTS: The within-run and the total-run precisions of the GEM Premier 4000 showed very low CV of 0.04~4.40% and 0.06~4.11%, respectively, in all parameters except the lactate, which had CV of 5.58% in Level 1 QC material. The system showed a good linearity (r2=0.997~1.000, systemic error=0.00~0.20%) for all items. Sample-related carryover was -4.35%~0.15%. In comparison with the NOVA CCX2 instrument, correlation was high in all parameters with the r value ranging from 0.983-0.999 except for carboxyhemoglobin (r=0.804) and methemoglobin (r=0.010) whose concentrations were in the lower level. CONCLUSIONS: GEM Premier 4000 showed good analytical performance required for blood gas analyzer in its precision, linearity, sample-related carryover, and close correlation with NOVA CCX2. It fulfills most of the requirements for both point-of-care and laboratory use.
Carboxyhemoglobin ; Lactic Acid ; Methemoglobin ; Quality Control

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Performance Evaluation of MassTrak LC/MS/MS Tacrolimus Kit.

Jaekwang NOH ; Heewon MOON ; Mina HUR ; Yeomin YUN

Journal of Laboratory Medicine and Quality Assurance.2009;31(1):199-205.

BACKGROUND: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) are used increasingly for tacrolimus monitoring. However, there are still variability of results due to home-brew reagents, so which cannot be warrantable data. We evaluated the analytical performance and clinical usefulness of a newly introduced MassTrak LC/MS/MS Tacrolimus kit (Waters Corporation, USA). METHODS: The performance of LC-MS/MS for determination of tacrolimus concentration were analyzed using patient samples and MassTrak LC/MS/MS Tacrolimus kit including calibrators, quality controls, internal standard, column and neat solution with respect to linearity, precision, lower limit of detection, lower limit of quantitation, sample carryover and comparison according to CLSI guidelines. The LC-MS/MS using home-brew reagents were performed for comparison test. RESULTS: The LC-MS/MS using MassTrak LC/MS/MS Tacrolimus kit showed a good linearity (R2> or =0.997) and precision (CV< 8%). Assigned LLOD (0.4 ng/mL) and LLOQ (0.8 ng/mL) were validated and carryover was estimated 0.5%. The system correlated well with the LC-MS/MS using home-brew reagents (R> or =0.974). CONCLUSIONS: LC-MS/MS using MassTrak LC/MS/MS Tacrolimus kit for determination of tacrolimus concentration showed good performance for linearity, precision, LLOD, LLOQ, carryover and comparison. Introduction of MassTrak LC/MS/MS Tacrolimus kit could be warranted results by manufacturer and useful for management of quality control.
Humans ; Indicators and Reagents ; Limit of Detection ; Mass Spectrometry ; Quality Control ; Tacrolimus

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