Usefulness of neutrophil gelatinase-associated lipocalin(NGAL) to confirm subclinical acute kidney injury and renal prognosis in patients following surgery / 고신대학교의과대학학술지

OBJECTIVES: The neutrophil gelatinase-associated lipocalin (NGAL) level following non cardiac surgery is useful for predicting acute kidney damage. However, there is insufficient conclusive evidence as to whether NGAL can be used to predict subclinical AKI following non-cardiac surgery. METHODS: We measured serum NGAL and creatinine levels in 41 patients following non-cardiac surgery, and the increase of these variables was used to predict acute decreases in kidney function. RESULTS: The study included a total of 41 patients. The mean age was 64.65 ± 17.09 years. The serum creatinine concentration was increased 12 hours after surgery. The mean SD serum NGAL decreased after 4hours after surgery and continued to decrease after 12 hours after surgery. The incidence of subclinical AKI determined by the 4 hour serum NGAL level was 10(24.4%), and the incidence of serum creatinine elevation was 0(0.0%). The incidence of subclinical AKI determined by the 12 hour serum NGAL level was 4(9.8%), and the incidence of subclinical AKI determined by serum creatinine was 4(9.8%). The elevation of NGAL was more rapid than the serum creatinine 4 hours after surgery. CONCLUSIONS: We verified the usefulness of the serum NGAL level as a predictive factor for subclinical AKI after non-cardiac surgery.

Evaluation of Centaur Syphilis, Immulite Syphilis, and Mediace TPLA for Detecting Treponemal Antibodies

BACKGROUND: We evaluated the efficacy of two chemiluminescence immunoassays that detect treponemal antibodies, Centaur Syphilis and Immulite Syphilis, in comparison with Mediace Treponema pallidum latex agglutination (TPLA). METHODS: The study was conducted in two phases. In the first phase, we tested 1,147 serum samples that were sequentially submitted for routine syphilis serology. In the second phase, we tested a panel of 119 frozen serum samples that had previously tested positive by Mediace RPR. The kappa value, total agreement percentage, and sensitivity and specificity were analyzed. RESULTS: Of the 1,147 random samples, 24 (2.09%) tested positive with Centaur Syphilis, 16 (1.39%) with Immulite Syphilis, and 19 (1.66%) with Mediace TPLA. Of the 119 Mediace RPR-positive samples, 103 (86.6%) tested positive with Centaur Syphilis, 101 (84.9%%) with Immulite Syphilis, and 105 (88.2%) with Mediace TPLA. The percent agreements (kappa values) were 98.8% (0.934) between Centaur Syphilis and Mediace TPLA, 99.0% (0.94) between Immulite Syphilis and Mediace TPLA, and 99.2% (0.955) between Centaur Syphilis and Immulite Syphilis. To measure the sensitivity and specificity of each treponemal test, samples showing agreement in three or four of the tests (three treponemal tests and Mediace-RPR) were regarded as true positive (n=117) or true negative (n=1,142). The respective values for sensitivity and specificity were 100% and 99.6% for Centaur Syphilis, 98.3% and 100% for Immulite Syphilis, and 99.2% and 99.7% for Mediace TPLA. CONCLUSIONS: Results from the three treponemal assays were in good agreement. Greater sensitivity of Centaur Syphilis and greater specificity of Immulite Syphilis were suggested.

Evaluation of Centaur Syphilis, Immulite Syphilis, and Mediace TPLA for Detecting Treponemal Antibodies

BACKGROUND: We evaluated the efficacy of two chemiluminescence immunoassays that detect treponemal antibodies, Centaur Syphilis and Immulite Syphilis, in comparison with Mediace Treponema pallidum latex agglutination (TPLA). METHODS: The study was conducted in two phases. In the first phase, we tested 1,147 serum samples that were sequentially submitted for routine syphilis serology. In the second phase, we tested a panel of 119 frozen serum samples that had previously tested positive by Mediace RPR. The kappa value, total agreement percentage, and sensitivity and specificity were analyzed. RESULTS: Of the 1,147 random samples, 24 (2.09%) tested positive with Centaur Syphilis, 16 (1.39%) with Immulite Syphilis, and 19 (1.66%) with Mediace TPLA. Of the 119 Mediace RPR-positive samples, 103 (86.6%) tested positive with Centaur Syphilis, 101 (84.9%%) with Immulite Syphilis, and 105 (88.2%) with Mediace TPLA. The percent agreements (kappa values) were 98.8% (0.934) between Centaur Syphilis and Mediace TPLA, 99.0% (0.94) between Immulite Syphilis and Mediace TPLA, and 99.2% (0.955) between Centaur Syphilis and Immulite Syphilis. To measure the sensitivity and specificity of each treponemal test, samples showing agreement in three or four of the tests (three treponemal tests and Mediace-RPR) were regarded as true positive (n=117) or true negative (n=1,142). The respective values for sensitivity and specificity were 100% and 99.6% for Centaur Syphilis, 98.3% and 100% for Immulite Syphilis, and 99.2% and 99.7% for Mediace TPLA. CONCLUSIONS: Results from the three treponemal assays were in good agreement. Greater sensitivity of Centaur Syphilis and greater specificity of Immulite Syphilis were suggested.

Evaluation of Flow Cytometric Crossmatch Results in Comparison with Donor-specific Antibodies Detected by Luminex-PRA Tests in Organ Transplantation Patients / 대한이식학회지

BACKGROUND: Two of the most sensitive methods for detecting donor-specific HLA antibodies (DSAs) are solid phase panel reactive antibody (PRA) assay using Luminex platform (Luminex-PRA), and a cell-based flow cytometric crossmatch (FCXM) test. We evaluated FCXM results in relation to DSAs detected by the Luminex-PRA method in solid organ transplantation candidates or post-transplant follow-up patients. METHODS: A total of 171 donor-recipient pairs were evaluated by Luminex-PRA (LIFECODES Class I and Class II ID kits; Gen-Probe, USA) and FCXM (T- and B-cells) tests. DSA levels were analyzed using a sum of median fluorescence intensity (MFI) values, and FCXM results were analyzed using MFI ratios. RESULTS: Class I and II DSAs were detected in 11.7% (20/171) and 11.1% (19/171) of tested sera, respectively. T-FCXM was negative in 97.4% (147/151) of Class I DSA negative sera, and B-FCXM was negative in 99.3% (137/138) of Class I and II DSA negative sera. T-FCXM was positive in 91.7% (11/12) of sera with moderate to strong Class I DSAs and B-FCXM was positive in 88.9% (16/18) of sera with moderate to strong Class II and/or Class I DSAs in the evaluation of sensitivities of FCXM in relation to DSA. There were significant correlations between FCXM ratios and DSA levels for both T-FCXM (P=0.008) and B-FCXM (P97%) and the sensitivities of T- and B-FCXM were satisfactory (>88%) in detecting moderate to strong DSAs.

Evaluation of an Automated Solid-phase Cell Adherence Assay in the Galileo System (Immucor) for Routine Pretransfusion Tests / 대한수혈학회지

BACKGROUND: In spite of a trend of automation for conducting most clinical laboratory tests, many blood banks are still dependent on manual tests. The aim of this study was to evaluate a full automation system called the Galileo (Immucor, USA) for conducting pretransfusion tests. METHODS: From August to October in 2009, a total of 3,002 cases of ABO-RhD typing and 1698 cases of antibody screening were compared between using manual tests and the Galileo system at Seoul National University Hospital, Seoul, Korea. For the manual tests, we used the slide method for ABO-RhD typing and the anti-human immunoglobulin treated microplate method for antibody screening. The Galileo system used the microplate method for ABO-RhD typing and the solid-phase red cell adherence (SPRCA) method for antibody screening. We calculated the overall concordance rate and the false positive or negative rates regarding the manual method as a standard test and the Galileo system as a comparative test. RESULTS: When comparing 3,002 cases of ABO-RhD typing, 52 cases (1.7%) were retested. A discrepancy between the two tests remained in 17 cases (0.6%) after repetition, which led to a concordance rate of 99.4% (2,985/3,002). On the comparison of 1,698 cases of antibody screening, 54 cases (3.2%) were retested. A discrepancy between the two tests remained for 30 cases (1.8%) and the concordance rate was 98.2% (1,615/1,698). Among the 20 false negative cases (1.2%), nine were thought to be cold antibodies with no cases of confirmed warm antibody. CONCLUSION: The automated Galileo system and the preexisting manual tests showed very good concordance for ABO-RhD typing and antibody screening. The Galileo system can be used with confidence for routine pretransfusion tests.

Usefulness of circulating vascular endothelial growth factor and neutrophil elastase as diagnostic markers of disseminated intravascular coagulation in non-cancer patients

BACKGROUND: Disseminated intravascular coagulation (DIC) is characterized by platelet and neutrophil activation. Platelets are the major source of circulating vascular endothelial growth factor (VEGF). Endostatin, an anti-angiogenic factor, is a fragment of collagen that is released from the extracellular matrix via the active cleavage of neutrophil elastase, thereby increasing the circulating level of endostatin. Hypercoagulable conditions such as DIC may induce the release of VEGF and neutrophil elastase from the platelets and neutrophils. METHODS: We enrolled 240 patients who were clinically suspected of having DIC. Plasma levels of VEGF, endostatin, and neutrophil elastase were determined using commercial ELISA kits. Patients were diagnosed as having overt DIC if the cumulative International Society on Thrombosis and Haemostasis Subcommittee score was >5. RESULTS: Overt DIC was diagnosed in 80 of the 240 patients. The circulating VEGF and neutrophil elastase levels gradually increased according to the severity of coagulopathy, as reflected by the DIC score. However, the circulating endostatin level did not change significantly according to the DIC score. We divided the patients into 2 groups: the non-cancer and cancer patient groups, to exclude the VEGF release from tumor tissues. Interestingly, in non-cancer patients, higher VEGF and neutrophil elastase levels were found to be significant diagnostic markers for overt DIC. CONCLUSION: Our findings suggest that circulating VEGF and neutrophil elastase levels are laboratory markers reflecting coagulation activity. They are expected to be potential diagnostic markers of overt DIC, especially in non-cancer patients.

Analysis of Panel Reactive Antibody in Patients Awaiting Renal Transplantation / 대한이식학회지

BACKGROUND: We performed panel reactive antibody (PRA) tests in renal transplantation candidates registered to the Korean Network for Organ Sharing (KONOS) and analyzed the results of PRA tests in relation to the results of HLA crossmatch (XM) tests and transplantation history. METHODS: From 833 patients awaiting cadaveric renal transplantation in the KONOS registry, 122 (98 patients) XM (NIH or AHG)-positive and 147 (147 patients) XM-negative serum samples were selected for PRA test. Enzyme linked immunosorbent assay (ELISA)-PRA screening test was performed and HLA antibody specificities were identified by NIH and AHG PRA methods. RESULTS: PRA positive rate was significantly higher in XM-positive group compared with XM-negative group (ELISA-PRA, 70.5% vs. 21.8%; AHG-PRA [PRA > or =10%], 73.9% vs. 9.6%). Donor specific antibodies were defined in 52.5% (64/122), whereas false positive XM results were suspected in 20.5% (25/122) of the XM-positive samples. Patients with transplantation histories showed significantly higher positive rates for ELISA-PRA (78.7% vs. 30.8%) and AHG-XM tests (78.2% vs. 29.3%). Highly sensitized patients (AHG-PRA > or =80%) showed significantly higher cumulative waiting rate (88.9% vs. 60.2% at 4 years) and longer waiting time (3.8 vs. 3.6 years) (Kaplan Meier method, P=0.037). PRA positive rate in the total renal transplantation candidates in the KONOS registry was estimated to be 33.9% for ELISA-PRA and 21.7% for AHG-PRA (PRA > or =10%), and the proportion of highly sensitized (PRA > or =80%) patients was estimated to be 5.4%. CONCLUSIONS: Pre-transplantation PRA as a routine test is needed in cadaveric renal transplantation for effective and fair allocation of organs in Korea.

The Effect of Pretransplantation Fetomaternal Microchimerism Detected in Peripheral Blood on Graft Survival in Renal Transplantation / 대한이식학회지

BACKGROUND: Microchimerism detected after solid organ transplatnation has been reported to be associated with improved graft survival with some controversies. However, the effect of pretransplantation microchimerism on the graft survival has not been studied to date. The aim of this study was to investigate the effect of pretransplantation fetomaternal microchimerism on the graft survival in renal transplantation. METHODS: A total of 27 cases of renal transplantation performed between mother and child pairs during the period from 1996 to 2004 at the Seoul National University Hospital were studied retrospectively. Presence of pretransplantation fetomaternal microchimerism was detected using DNA samples extracted from peripheral blood collected before the operation. Microchimerism for the HLA-DRB1 gene of non-inherited maternal antigen was detected using nested PCR-single strand conformation polymorphism (SSCP) method. The function and survival of allograft was compared between the groups with and without microchimerism. RESULTS: Microchimerism was detected in 10 (37%) of the 27 cases. In the group with microchimerism, serum creatinine levels at one and three years after transplantation tended to be lower in the patients with microchimerism than in those without microchimerism (one year, 1.1 vs 1.3 mg/dL, P=0.133; three years, 1.2 vs 1.5 mg/dL, P=0.083). The rejection free survival tended to be longer in the patients with microchimerism than in those without microchimerism (113.5 vs 72.5 months, P=0.146). CONCLUSIONS: This study was limited by small number of cases, and an extended study on a larger number of patients is needed to clarify the role of pretransplantation fetomaternal microchimerism on allograft survival.

A Comparison of Two Microcolumn Agglutination Systems for Red Cell Antibody Screening and Identification / 대한수혈학회지

BACKGROUND: The use of the microcolumn agglutination method for red cell antibody screening and identification is on the increase because it has several advantages over the conventional tube method. The aim of this study was to compare two microcolumn agglutination systems, the Ortho BioVue (Ortho-clinical Diagnostics, Amershman, Bucks, UK) and the DiaMed-ID (DiaMed Ag, Cressier, Morat, Switzerland), which are both popularly used in Korea. METHODS: We used 897 consecutive serum samples that were requested to undergo red cell antibody screening. They were collected from February, 2008 to March, 2008 at Seoul National University Boramae Hospital. All the serum samples were screened for red cell antibody by both microcolumn agglutination systems, and any positive sample by either of the two systems was re-tested for antibody identification by both systems. We followed the instructions of each manufacturer and we used the LISS/Coombs microcolumn agglutination method for red cell antibody screening and identification. RESULTS: The rate of positive screening was 0.8% by the Ortho BioVue and 0.7% by the DiaMed-ID with insignificant differences between the two systems (P=0.439). The two systems showed excellent overall concordance in screening, 99.4%. Among the 9 samples with positive screening results, we found specific antibodies in only four samples. The rate of identification was 29% (2/7) by the Ortho BioVue and 33% (2/6) by the DiaMed-ID. CONCLUSION: Both methods were very comparable on performing red cell antibody detection and identification. Thus, they could both be used in laboratories for routine tests in such a way as to compensate for any shortcomings of the other method.

A Comparison of Two Microcolumn Agglutination Systems for Red Cell Antibody Screening and Identification / 대한수혈학회지

BACKGROUND: The use of the microcolumn agglutination method for red cell antibody screening and identification is on the increase because it has several advantages over the conventional tube method. The aim of this study was to compare two microcolumn agglutination systems, the Ortho BioVue (Ortho-clinical Diagnostics, Amershman, Bucks, UK) and the DiaMed-ID (DiaMed Ag, Cressier, Morat, Switzerland), which are both popularly used in Korea. METHODS: We used 897 consecutive serum samples that were requested to undergo red cell antibody screening. They were collected from February, 2008 to March, 2008 at Seoul National University Boramae Hospital. All the serum samples were screened for red cell antibody by both microcolumn agglutination systems, and any positive sample by either of the two systems was re-tested for antibody identification by both systems. We followed the instructions of each manufacturer and we used the LISS/Coombs microcolumn agglutination method for red cell antibody screening and identification. RESULTS: The rate of positive screening was 0.8% by the Ortho BioVue and 0.7% by the DiaMed-ID with insignificant differences between the two systems (P=0.439). The two systems showed excellent overall concordance in screening, 99.4%. Among the 9 samples with positive screening results, we found specific antibodies in only four samples. The rate of identification was 29% (2/7) by the Ortho BioVue and 33% (2/6) by the DiaMed-ID. CONCLUSION: Both methods were very comparable on performing red cell antibody detection and identification. Thus, they could both be used in laboratories for routine tests in such a way as to compensate for any shortcomings of the other method.

A Case of ABO*Ael02/O04 Genotype with Typical Phenotype O / 대한진단검사의학회지

Ael is a rare blood type which has the least amount of A antigen among A subgroups. It can be detected by special tests performed to resolve the discrepancy between red cell and serum typing in routine serological typing. The presence of A antigen on Ael red cell is demonstrable only by adsorption and elution tests. An Ael individual does not secret A substance in the saliva and may have anti-A antibody in the serum which is usually less reactive with the reagent red cells than anti-B antibody. In Korea, Ael02 has been reported more frequently than other Ael alleles. We report a case of Ael02/O04 who presented as typical phenotype O with strong anti-A and anti-B antibodies and no A antigen detected even by adsorption and elution tests. The case has been proved to be Ael02/O04 by direct sequencing analysis. In individuals with history of discrepancies in the results of ABO phenotyping, ABO genotyping is needed for an accurate evaluation of their blood type.