Hanah Kim

Plasma neutrophil gelatinase-associated lipocalin as a biomarker for acute kidney injury in critically ill patients with suspected sepsis.

OBJECTIVES The aim of this study was to investigate the diagnostic utility of plasma neutrophil gelatinase-associated lipocalin (NGAL) as an early objective biomarker to predict acute kidney injury (AKI) in critically ill patients with suspected sepsis, for whom procalcitonin (PCT) was used for the diagnosis and staging of sepsis. DESIGN AND METHODS Plasma NGAL was measured using the Triage NGAL Test (Alere, Inc., San Diego, CA, USA) in 231 samples obtained from patients with suspected sepsis. The results of NGAL were compared with those of Elecsys BRAHMS PCT (Roche Diagnostics, Basel, Switzerland). Renal failure was assessed using the renal subscore of Sepsis-related Organ Failure Assessment (SOFA) score. AKI was defined according to the Acute Kidney Injury Network criteria. RESULTS The concentrations of plasma NGAL were significantly different according to the five groups of PCT concentration (P<0.0001) and the renal subscore of SOFA score (P<0.0001). Plasma NGAL was significantly increased in the patients with AKI compared with those without AKI (416.5 ng/mL vs. 181.0 ng/mL, P=0.0223). CONCLUSION Plasma NGAL seems to be a highly sensitive and objective predictor of AKI in patients with sepsis. Plasma NGAL can be added for the diagnosis and staging of renal failure in sepsis.

Analytical performance evaluation of the scanning capillary tube viscometer for measurement of whole blood viscosity.

BACKGROUND Whole blood viscosity (WBV) is the resistance of blood flow in blood vessels. Increased WBV may be a cardiovascular risk factor. The proper screening of WBV can help the early detection of cardiovascular disease. We investigated the performance of a new scanning capillary tube viscometer (SCTV) for the measurement of WBV. METHODS We evaluated the total precision of the SCTV for 20 days using three control viscosity materials, and the within-day precision with the whole blood samples of three different individuals. For the linearity evaluation, serial dilutions of a high concentration standard material were used. For the method comparison, the results of the SCTV method were compared to those of Brookfield rotating viscometer on 227 subjects. RESULTS The SCTV had good within-run and total-run coefficient of variant (CV)s at low-, medium-, and high-concentration samples, at shear rates of 1 and 300 s(-1). The within-day CVs with the three human blood samples were 6.3%, 3.7% and 3.8% at a shear rate of 1s(-1), and 3.2%, 3.0% and 4.1% at a shear rate of 300 s(-1). The SCTV method showed an excellent linearity in the range of 84.9 to 558.2 milliPoise (mP) and 28.8 to 71.0 mP at shear rates of 1 and 300 s(-1), respectively. For the comparison study, the SCTV and the rotating viscometer showed comparable results. CONCLUSIONS The SCTV showed a stable analytical performance, and was comparable with the rotational viscometer. This new SCTV method can be used in the clinical laboratory for various needs.

Streptococcus suis causes septic arthritis and bacteremia: phenotypic characterization and molecular confirmation.

Streptococcus suis is a swine pathogen that causes meningitis, septicemia, pneumonia, and endocarditis. The first case of human S. suis infection was reported in Denmark in 1968, and since then, this infection with has been reported in many countries, especially in Southeast Asia because of the high density of pigs in this region. We report the case of a patient with septic arthritis and bacteremia caused by S. suis. Cases in which S. suis is isolated from the joint fluid are very rare, and to the best of our knowledge, this is first case report of S. suis infection in Korea. The identity of this organism was confirmed by phenotypic characterization and 16S rRNA sequence analysis. An 81-yr-old Korean woman who presented with fever, arthralgia, and headache was admitted to a secondary referral center in Korea. Culture of aspirated joint fluid and blood samples showed the growth of S. suis biotype II, which was identified by the Vitek2 GPI and API 20 Strep systems (bioMérieux, USA), and this organism was susceptible to penicillin G and vancomycin. The 16S rRNA sequences of the blood culture isolates showed 99% homology with those of S. suis subsp. suis, which are reported in GenBank. The patients fever subsided, and blood and joint cultures were negative for bacterial growth after antibiotic therapy; however, the swelling and pain in her left knee joint persisted. She plans to undergo total knee replacement.

Reference interval for immature platelet fraction on Sysmex XN hematology analyzer: a comparison study with Sysmex XE-2100

Abstract Background: Recently introduced hematology analyzer, the Sysmex XN modular system (Sysmex, Kobe, Japan), has newly adopted a florescent channel to detect platelets and immature platelet fraction (IPF). This study aimed to establish new reference intervals for %-IPF and absolute number of IPF (A-IPF) on Sysmex XN. Platelet counts, %-IPF, and A-IPF were also compared between Sysmex XN and XE-2100 systems (Sysmex). Methods: Except outliers, blood samples from 2104 healthy individuals and 140 umbilical cord blood were analyzed using both Sysmex XN and XE-2100. The results of two systems were compared using Bland-Altman plot. The reference intervals for %-IPF and A-IPF were defined using non-parametric percentile methods according to the Clinical and Laboratory Standard Institute guideline (C28-A3). Results: The platelet counts, %-IPF, and A-IPF showed non-parametric distributions. The mean difference between Sysmex XN and XE-2100 in healthy individuals revealed a positive bias in platelets (+8.0×109/L), %-IPF (+1.2%), and A-IPF (+3.0×109/L). The reference intervals for %-IPF and A-IPF on Sysmex XN were: 1.0%–7.3% and 2.49–15.64×109/L in healthy individuals; and 1.0%–4.4% and 2.94–12.82×109/L in umbilical cord blood. Conclusions: This large-scale study demonstrates a clear difference of platelet counts and IPF between Sysmex XN and XE-2100. The new reference intervals for IPF on Sysmex XN would provide fundamental data for clinical practice and future research.

Performance evaluation of Sysmex XN hematology analyzer in umbilical cord blood: a comparison study with Sysmex XE-2100

Abstract Background: The Sysmex XN (XN) modular system (Sysmex, Kobe, Japan) is a new automated hematology analyzer equipped with different principles from its previous version, Sysmex XE-2100. We compared the performances of Sysmex XN and XE-2100 in umbilical cord blood (CB) specimens. Methods: In 160 CB specimens, complete blood count (CBC) parameters and white blood cells (WBC) differentials were compared between the two analyzers. Their flagging performances for blasts, abnormal/atypical lymphocytes, immature granulocytes and/or left-shift (IG), and nucleated red blood cells (NRBC) counts were compared with manual counts. For the blast flagging, Q values by Sysmex XN were further compared with manual slide review. Results: Sysmex XN and XE-2100 showed high or very high correlations for most CBC parameters but variable correlations for WBC differentials. Compared with XE-2100, XN showed significantly different flagging performances for blasts, abnormal/atypical lymphocytes, and IG. The flagging efficiency for blasts was significantly better on Sysmex XN than on XE-2100 (85.0% vs. 38.8%): Sysmex XN showed a remarkably increased specificity of blast flag, compromising its sensitivity of blast flag. Among the 24 specimens with blasts (range, 0.5%–1.5%), only one (4.2%) showed a positive Q value. Conclusions: This study highlighted the remarkable differences of flagging performances between Sysmex XN and XE-2100 in CB specimens. The Sysmex XN modular system seems to be a suitable and practical option for the CB specimens used for hematopoietic stem cell transplantation as well as for the specimens from neonates.

Latent tuberculosis infection screening for laboratory personnel using interferon-γ release assay and tuberculin skin test in Korea: an intermediate incidence setting

Background: Though recent reports have indicated a higher prevalence of latent tuberculosis infection (LTBI) in laboratory personnel than in other healthcare workers, these studies included only a limited number of laboratory personnel. Methods: We have thus focused on the laboratory personnel, who had a high level of exposure to specimens from patients with TB. We recruited 173 laboratory personnel and performed QuantiFERON‐TB Gold In‐Tube test (QFT‐G) and tuberculin skin test (TST). Results: QFT‐G was positive in 21.4% of the enrolled laboratory personnel, and TST was positive in 33.3%. The agreement between the two tests was fair (κ = 0.234). In multivariate analyses, household contactwith TBpatients (P = 0.013), the laboratory sections of microbiology (P = 0.045) and chemistry/immunology (P = 0.014) were shown to be significantly associated with positive QFT‐G results. Conclusion: Our data show a high prevalence of TST and QFT‐G positivity in laboratory personnel and emphasize the importance of LTBI screening for laboratory personnel. In BCG‐vaccinated populations with an intermediate incidence setting, QFT‐G seems to be superior to TST as a screening tool for the detection of LTBI. Further study, including results of follow‐up tests will be helpful for confirmation of our findings. J. Clin. Lab. Anal. 25:382–388, 2011.

Soluble ST2 Has a Prognostic Role in Patients With Suspected Sepsis

Background Soluble suppression of tumorigenicity 2 (sST2) has emerged as a novel biomarker for heart failure, and serum sST2 concentrations could be increased in inflammatory diseases. We explored whether sST2 is related to cardiac dysfunction/failure and has a prognostic role in patients with suspected sepsis. Methods In a total of 397 patients with suspected sepsis, sST2 concentrations were measured by using the Presage ST2 Assay (Critical Diagnostics, USA). sST2 concentrations were analyzed according to procalcitonin (PCT) concentrations, cardiovascular subscores of the sepsis-related organ failure assessment (SOFA) score, and clinical outcomes. Results sST2 concentrations were increased significantly according to the five groups of PCT concentrations and cardiovascular subscores of the SOFA score (P<0.000001 and P=0.036, respectively). In-hospital mortality was significantly higher among patients with sST2 concentrations above 35 ng/mL (P=0.0213) and among patients with increased concentrations of both sST2 and PCT (P=0.0028). Conclusions sST2 seems to be related to both cardiac dysfunction/failure and severity in sepsis. Measurement of sST2 and PCT in combination would be useful for risk stratification and prognosis prediction in patients with suspected sepsis.

Comparison of International Normalized Ratio Measurement between CoaguChek XS Plus and STA-R Coagulation Analyzers.

Background. Point-of-care testing (POCT) coagulometers are increasingly being used in the hospital setting. We investigated whether the prothrombin time international normalized ratio (INR) results by CoaguChek XS Plus (Roche Diagnostics GmbH, Mannheim, Germany) can be used reliably without being confirmed with the INR results by STA-R system (Diagnostica Stago S.A.S, Asnières sur Seine, France). Methods. A total of 118 INR measurements by CoaguChek XS Plus and STA-R were compared using Passing/Bablok regression analysis and Bland-Altman plot. Agreement of the INR measurements was further assessed in relation to dosing decision. Results. The correlation of INR measurements between CoaguChek XS Plus and STA-R was excellent (correlation coefficient = 0.964). The mean difference tended to increase as INR results increased and was 0.25 INR in the therapeutic range (2.0-3.0 INR). The overall agreement was fair to good (kappa = 0.679), and 21/118 (17.8%) INR measurements showed a difference in dosing decision. Conclusion. The positive bias of CoaguChek XS Plus may be obvious even in the therapeutic INR range, and dosing decision based on the CoaguChek XS Plus INR results would be different from that based on the STA-R results. The INR measurements by POCT coagulometers still need to be confirmed with the laboratory INR measurements.

Comparison of two multiplex PCR assays for the detection of respiratory viral infections.

Respiratory viruses are the main causes of upper and lower respiratory tract diseases. Rapid and accurate detection of respiratory viruses is crucial for appropriate patient treatment and prevention of endemic spread.

Distribution of CD4+CD25highFoxP3+ regulatory T-cells in umbilical cord blood

Objective: This study aimed to establish reference intervals for lymphocyte subsets including CD4+CD25highFoxP3+ regulatory T-cells (Tregs) in umbilical cord blood. Methods: Umbilical cord blood was obtained after birth from 120 healthy full-term neonates, who were born between November 2010 and November 2011. Lymphocyte subsets including Tregs were analysed using flow cytometer (Beckman Coulter, Fullerton, CA, USA), and the reference intervals were defined using non-parametrical percentile methods according to the Clinical and Laboratory Standard Institute guideline (C28-A3). Results: The reference intervals for lymphocyte subsets were: helper T-cells (CD3+/CD4+), 15.40–70.06%; cytotoxic T-cells (CD3+/CD8+), 9.65–34.28%; B-cells (CD19+), 4.50–29.59%; and natural killer cells (CD3−/CD16+/CD56+), 1.42–28.03%. The reference interval for Tregs was 0.35–9.07%. Conclusions: This study provides the reference intervals for lymphocyte subsets including Tregs in umbilical cord blood from healthy full-term neonates. These results could be used as fundamental data for clinical laboratory tests as well as future researches.