A case of toxic epidermal necrolysis due to topiramate

Topiramate is an antiepileptic drug effective for multiple types of seizure and is also used to prevent migraine attack. Several side effects have been reported, such as metabolic acidosis, nephrolithiasis, anorexia, weight reduction, drowsiness, glaucoma, hyperthermia, and cognitive dysfunction, whereas skin manifestationis were rarely reported. We report a case of a 12-year-old girl on medication of topiramate for 8 months due to focal epilepsy. She had fever, sore throat, burning sense in the vaginal area, and then flaccid bullae and erythematous patches proceeded to the whole bodyskin and mucosa including the conjunctiva, oral cavity, and genital areas. She was diagnosed with toxic epidermal necrolysis (TEN) and improved after the discontinuation of topiramate and with administration of high-dose intravenous steroid and immunoglobulin. We, herein, report a girl who developed severe side effects on the skin, TEN, due to topiramate.

Diagnostic Algorithm for the Rapid and CostEffective Detection of Clostridioides difficile Infection: Comparison between C. DIFF QUIK CHEK COMPLETE and VIDAS GDH & Toxin Assay

Background@#We evaluated the analytical performance and cost-effectiveness of lateral flow immunoassays (LFIAs) in detecting Clostridioides difficile glutamate dehydrogenase (GDH) antigen and toxin A/B, followed by a rapid nucleic acid amplification test (NAAT). @*Methods@#A total of 341 unformed stools were tested using a two-step algorithmic approach with C. DIFF QUIK CHEK COMPLETE (QCC) LFIA (TechLab, USA), followed by Xpert C. difficile NAAT (Xpert). The performance of the QCC assay was compared with that of the VIDASC. difficile GDH and toxin A/B assay (bioMérieux, France), an enzyme-linked fluorescence im munoassay. The clinical performance and cost-effectiveness of the diagnostic algorithms using the QCC or VIDAS assays were compared to the results obtained using the Xpert assay alone. @*Results@#For GDH and toxin detection, the QCC and VIDAS assays dem onstrated an almost perfect agreement, with no significant difference in sensitivity (QCC-GDH, 90.5%; VIDAS-GDH, 91.9%; QCC-toxin, 51.4%; VIDAStoxin, 55.4%) and specificity (QCC-GDH, 92.9%; VIDAS-GDH, 89.1%; QCC-toxin, 100%; VIDAS-toxin, 99.6%), compared to the Xpert. The algorithmic approach (GDH and toxin plus Xpert) increased the sensitivity (QCC, 93.2%; VIDAS, 94.6%) and specificity (QCC, 100%; VIDAS, 99.6%). The algorithmic approach reduced the cost compared to the Xpert alone, and the turnaround time of the QCC was shorter than that of the VIDAS assay. @*Conclusions@#Simultaneous detection of GDH and toxin A/B, using QCC or VIDAS assays showed comparable sensitivity and specificity when followed by the Xpert assay. The QCC assay is preferable in turnaround time and cost, which are important considerations for laboratories handling smaller number of samples.

Detection of Respiratory Viruses and Atypical Bacterial Pathogens in Infants with Acute Respiratory Infections Using Multiplex PCR / 대한임상미생물학회지

Multiplex PCR of nasopharyngeal aspirates detected viruses and atypical bacteria in 75.3% (219/291) of infants with acute respiratory infections from July 2010 to June 2013. Frequent viruses were human rhinovirus (29.9%), parainfluenza virus (21.7%), respiratory syncytial virus (17.9%), and human metapneumovirus (10.3%). Mycoplasma pneumoniae and Bordetella pertussis were detected in 3.4% and 0.3%, respectively.

Factors associated with various clinical manifestations of Mycoplasma pneumonia in children

PURPOSE: Mycoplasma pneumonia (MP) is a major cause of community-acquired pneumonia in children and young adults. We aimed to investigate the factors that may influence on the clinical manifestations of MP in children. METHODS: A total of 109 admitted children from October 2011 to February 2012 were prospectively enrolled with physical examination and laboratory tests (complete blood count, C-reactive protein [CRP], and particle agglutinin assay). The diagnosis of MP was made when there was an infiltration on the chest X-ray and the particle agglutination test was once over 1:640 or showed 4-fold increase in serial tests. They were grouped by age, fever duration after treatment, presence of pleural effusion and wheezing. RESULTS: Preschool children showed shorter duration of fever (P=0.001), more wheezing (P3 days) and pleural effusion were developed in children with higher CRP (P=0.018 and P=0.007). Wheezing has been developed in children with younger age (P=0.007). CONCLUSION: Younger age was a risk factor to develop wheezing in MP and prolonged fever and pleural effusion were more likely to develop in children with higher CRP.

Clinical Course after Intravitreal Bevacizumab Injection in Ischemic Central Retinal Vein Obstruction

PURPOSE: To determine the clinical outcome of intravitreal bevacizumab injection in patients with ischemic central retinal vein obstruction (CRVO). METHODS: The present study was conducted retrospectively on 56 eyes of 56 patients who were diagnosed with CRVO and classified according to ischemic and non-ischemic type and underwent an intravitreal bevacizumab injection. The present study measured changes in visual acuity and central macular thickness, neovascularization in the anterior segment, development of neovascular glaucoma and other clinical complications. RESULTS: The average number of bevacizumab injections in both groups was 2.07 and 1.62 in the ischemic type. No patients developed neovascular glaucoma in the non-ischemic type group, 14 of 26 eyes in the ischemic type group developed neovascular glaucoma and the mean time to diagnosis was 28.75 weeks. log MAR visual acuity of the ischemic type group prior to injection was 1.56 +/- 0.65 on average which improved to 1.44 +/- 0.97 (p = 0.45). CONCLUSIONS: Intravitreal bevacizumab injection improves the condition of cystic macular edema clinically, but does not affect the development of neovascular glaucoma and improvement of visual acuity in ischemic type CRVO.

Outbreak of Swine-Origin Influenza A (H1N1); Experience of a Regional Center in Seoul during a Month, August-September 2009 / 대한임상미생물학회지

BACKGROUND: The aim of this study is to clarify the epidemiology of swine-origin influenza A (H1N1) virus 2009 (S-OIV) during the first month of outbreak at one of influenza clinic in Seoul, Korea. METHODS: We documented the epidemiologic and clinical features of S-OIV-confirmed cases who visited a university hospital in Northeastern Seoul between August 21 and September 20, 2009. Nasopharyngeal swab of patients with acute febrile respiratory illnesses were evaluated with rapid influenza antigen tests and multiplex RT-PCR for S-OIV and seasonal influenza A. RESULTS: A total of 5,322 patients with acute febrile respiratory illnesses were identified at our influenza clinic for the study period. S-OIV was confirmed in 309 patients by RT-PCR. The patients ranged from 2 months to 61 years of age and 189 patients (61.2%) were teenagers. Eighty-one patients had known contact with S-OIV-confirmed patients in schools (N=61), households (N=15), and healthcare facilities (N=3). Frequent symptoms were fever (94.5%), cough (73.1%), sore throat (52.1%), and rhinorrhea (50.5%). Gastrointestinal symptoms were also present in 10 patients (4.9%). Ten patients (4.9%) required hospitalizations. Seventy patients (22.7%) could not take oseltamivir at the first visits, however, all of them recovered without complication. Rapid antigen tests showed the sensitivity of 44.4% (130/294). Patients with positive antigen tests, compared with negative antigen tests, showed higher frequencies of rhinorrhea (60.8% vs 43.3%, P=0.004) and stuffy nose (33.8% vs 20.1%, P=0.012). CONCLUSION: S-OIV infections spread predominately in school-aged children during the early accelerating phase of the outbreak. Rapid influenza antigen tests were correlated with nasal discharge and obstruction.

A case of hemophagocytic syndrome complicated by acute viral hepatitis A infection / 대한간학회지

Hemophagocytic syndrome (HPS) is a rare but serious condition that is histopathologically characterized by activation of macrophage or histiocytes with hemophagocytosis in bone marrow and reticuloendothelial systems. Clinically it presents with high fever, hepatosplenomegaly, pancytopenia, liver dysfunction, and hyperferritinemia. Hepatitis A virus is a very rare cause of secondary HPS. We report a case of a 22-year-old woman infected by hepatitis A virus who was consequently complicated with HPS. She presented typical clinical features of acute hepatitis A, and showed clinical and biochemical improvements. However, HPS developed as a complication of acute hepatitis A and the patient died of intraperitoneal bleeding caused by hepatic decompensation and disseminated intravascular coagulation.

Recombinant Chromosome 4 with Partial 4p Deletion and 4q Duplication Inherited from Paternal Pericentric Inversion / 대한진단검사의학회지

Pericentric inversion of chromosome 4 can give rise to 2 alternate recombinant (rec) chromosomesby duplication or deletion of 4p. The deletion of distal 4p manifests as Wolf-Hirschhorn syndrome (WHS). Here, we report the molecular cytogenetic findings and clinical manifestations observed in an infant with 46,XX,rec(4)dup(4q)inv(4)(p16q31.3)pat. The infant was delivered by Cesarean section at the 33rd week of gestation because pleural effusion and polyhydramnios were detected on ultrasonography. At birth, the infant showed no malformation or dysfunction, except for a preauricular skin tag. Array comparative genomic hybridization analysis of neonatal peripheral blood samples showed a gain of 38 Mb on 4q31.3-qter and a loss of 3 Mb on 4p16.3, and these results were consistent with WHS. At the last follow-up at 8 months of age (corrected age, 6 months), the infant had not achieved complete head control.

Current Status of External Quality Assessment of Fecal Occult Blood Test / 대한진단검사의학회지

BACKGROUND: Nationwide external quality assessment (EQA) of the fecal occult blood test (FOBT) in Korea was first introduced in 2007-2009. The EQA results were analyzed to assess the current status of FOBT and to plan the continuation of the EQA program. METHODS: The surveys included 40 hospitals in the preliminary survey conducted in 2007, 249 general hospitals in 2008, and 389 hospitals in 2009. In the surveys, the participating hospitals provided the results of the distributed materials and replies to the questionnaire on the FOBT test procedures and quality controls. RESULTS: In the surveys conducted between 2007 and 2009, a total of 650 institutes submitted 653 test system results; 3 institutes used 2 kinds of methods. All of the institutes used immunologic methods; 107 institutes (16.5%) used quantitative equipments and 546 institutes (84.0%) used qualitative kits. Most quantitative tests yielded consistent positive or negative results; however, their cut-off and measured values differed according to the equipments used. A low-level material tested in 2007 was negative in the quantitative methods but positive in some qualitative methods because of lower detection limits. The discordance rates among quantitative tests were 3.2% in 2007, 4.4% in 2008, and 0% in 2009 and the rates among qualitative tests were 13.8% in 2008 and 2.6% in 2009. Semi-solid EQA materials showed the ability to evaluate the overall test procedures with acceptable stability. CONCLUSIONS: In the first Korean FOBT EQA, commercially available EQA materials were proven to be stable. Continuation of the EQA program and further education of laboratory personnel are needed to reduce inconsistency in results. Further, the test kit, procedures, and result reports must be standardized.

Meta-Analysis for the Pooled Sensitivity and Specificity of anti-Human Immunodeficiency Virus Ab Rapid Tests / 대한진단검사의학회지

BACKGROUND: Many immunochromatography (ICA) kits for anti-human immunodeficiency virus type (HIV) antibody (Ab) have been introduced to improve the accessibility of HIV Ab tests. However, qualified evaluation reports for HIV rapid tests are not enough to validate their performances. Metaanalysis for the performances of the HIV Ab rapid tests was performed in this study. METHODS: PubMed database was searched with combination of search terms, 'human immunodeficiency virus', 'HIV Ab', 'rapid test', 'immunochromatography', 'performance', 'sensitivity', and 'specificity'. Criteria of inclusion were performance studies for HIV ICA kits with serum or EDTA whole blood. Methodological qualities were evaluated with standards for reporting of diagnostic accuracy studies (STARD) checklists by two investigators. Homogeneity among selected studies was evaluated and then pooled sensitivity and specificity were calculated. Positive and negative predictive values were simulated with presumed HIV prevalence in Korea. RESULTS: Twenty-three studies were selected from 12 high-qualified papers with STARD checklists. The performance of 23 studies were found to be heterogeneous (P<0.1) and random effect model was used. Pooled sensitivity was 99.71% (95% CI: 99.45-99.97%) and pooled specificity was 99.27% (95% CI: 98.83-99.70%). With HIV prevalence of 0.03%, positive and negative predictive values were presumed to be 3.936% and 99.999%, respectively. CONCLUSIONS: This meta-analysis for HIV ICA rapid tests showed good performance. In consideration of low positive predictive values of HIV rapid tests, confirmation by enzyme immunoassay or Western blot is still needed. This study would be helpful in evaluating and establishing proper performance guideline for those kits not fully evaluated.

A Case of Hantavirus Pulmonary Syndrome Mimicking Apalastic Anemia with Invasive Aspergillosis

Hantavirus is known to a causative agent of hemorrhagic fever with renal syndrome and it can cause hantavirus pulmonary syndrome, a rare disease in Korea. Hantavirus pulmonary syndrome is usually associated with pulmonary hemorrhage and fever. The common hematologic features of this syndrome are elevated hematocrit level, leukocytosis and thrombocytopenia. We report a case of hantavirus pulmonary syndrome with pancytopenia. This patient with severe neutropenia with pulmonary infiltration mimicked aplastic anemia with invasive aspergillosis.

Influence of the Pre-Analytical Specimen Storage Conditions on the Fecal Occult Blood Test Results / 대한진단검사의학회지

BACKGROUND: Korean national cancer screening program selected fecal occult blood test (FOBT) as a primary screening method of colorectal carcinoma in adult > or =50 yr old irrespective of symptom. Notice to pre-analytical errors is especially important for the FOBT because examinees collect and submit their specimens to laboratories by themselves. We examined the influences of the fecal storage temperatures, durations and with or without buffer on the FOBT results. METHODS: Thirty FOBT-positive specimens above 100 ng/mL were used for the study from July to August 2008. Quantitative FOBT was performed with OC-sensors II (Eiken Chemical Co., Japan). Each specimen was divided into 4 groups. Two groups in plastic buffer-free containers were kept either at 4degrees C or room temperature (25-28degrees C), respectively. Another two groups in buffer-tubes were also kept either at 4degrees C or room temperature. Each group was repeatedly examined with same method every 24 hr up to 120 hr. RESULTS: Eleven specimens (36.7%) in buffer-free containers converted to negative results (below the 100 ng/mL) after 24 hr and 17 specimens (56.7%) did after 48 hr at room temperature. Ten specimens (33.3%) in buffer-free containers converted to negative after 48 hr at 4degrees C. Specimens contained in buffer-tubes showed little change; 3 specimens (10.0%) at room temperature and no specimen at 4degrees C showed negative conversions after 48 hr. CONCLUSIONS: Buffer-tube minimizes false negative FOBT results during pre-analytical delay of specimen. The examinees using buffer-free containers need to be educated to hand in their specimens to laboratories as soon as possible.

Comparison of Two Enzyme Immunoassay for Detection of Clostridium difficile Toxin A and Toxin B / 대한진단검사의학회지

BACKGROUND: Enzyme immunoassay (EIA) capable of detecting both toxin A and toxin B is strongly recommended for the diagnosis of Clostridium difficile associated disease. Therefore, we evaluated two different EIAs for the detection of C. difficile toxin A/B. METHODS: For a total of 228 stool specimens we performed bacteriologic cultures for C. difficile and examined for toxin A and toxin B using enzyme linked fluorescent immunoassay (ELFA; VIDAS CDAB, Bio-Merieux sa, France) and ELISA (C.DIFFICILE TOX A/B II, TECHLAB, USA). We also performed PCR assays for toxin A and B genes in 117 C. difficile isolates that grew from the stool cultures and compared the results with those obtained with the two different EIAs. RESULTS: The concordance rate between ELFA and ELISA was 85.5% (195/228). Using the culture and PCR results as the standard, the sensitivity/specificity of the ELFA and ELISA were 65.0%/72.1% and 71.8%/70.3%, and for positive/negative predictive values were 78.4%/69.6% and 71.8%/70.3%, respectively (P value >0.05). No differences were observed between the results of ELFA and ELISA with toxin A- toxin B+ strains of C. difficile. CONCLUSIONS: The sensitivity of the ELISA was slightly higher than that of ELFA for toxin A and toxin B, but the specificity and positive predictive value of the ELFA were rather higher than those of the ELISA, although no statistical differences were observed. A bacteriologic culture and PCR assay for toxin genes are recommended in case the both EIAs are negative.

Co-circulation of Two Genotypes of Hepatitis A Virus from Sporadic Cases in Northeastern Area of Seoul, Korea / 대한진단검사의학회지

BACKGROUND: In previous studies, most hepatitis A virus (HAV) isolates had been genotype IA in Korea. Recently, a small number of different genotypes were reported with an upsurge of acute hepatitis by HAV. We investigated the distribution of HAV genotypes. METHODS: RNA was extracted from anti-HAV IgM positive sera which were collected from March 2007 to February 2008 at a tertiary care hospital in Northeastern Seoul, Korea. Nested reverse transcription (RT)-PCR and direct sequencing for VP1/P2A region of the HAV were performed. RESULTS: A total of 699 cases with suspected acute hepatitis were tested for anti-HAV IgM, and positive results were obtained in 56 sera (8.0%), which were collected 2 to 15 days (median, 7 days)after the onset of symptoms. Of the 56 seropositive samples, 52 (92.9%) were positive for HAV RNA, among which 28 isolates (53.8%) belonged to genotype IA and the remaining 24 (46.2%) belonged to genotype IIIA. Both IA and IIIA genotypes were isolated from 6-7 neighboring administrative districts throughout the year without geographic or seasonal restrictions. CONCLUSIONS: Co-circulation of two distinct HAV genotypes (IA and IIIA) was observed from the northeastern Seoul for the year studied.

The effect of 6% hydroxyethyl starch (670/0.75) on hemostasis during acute normovolemic hemodilution / 대한마취과학회지

BACKGROUND: Hydroxyethyl starch (HES), a widely used plasma volume expander, has been associated with platelet dysfunction and inhibition of coagulation. Six% HES (Molecular weight 670 kd, molar substitution 0.75) is a plasma volume expander in a physiologically balanced medium of electrolytes, lactate and glucose. The aim of this study is to evaluate the effect of 6% HES (670/0.75) on hemostasis during acute normovolemic hemodilution (ANH). METHODS: Eighteen healthy adult male patients scheduled for spine surgery were enrolled in this study. Before general anesthesia, patients underwent ANH with 20 ml/kg of 6% HES (670/0.75). Hemoglobin, platelet count, plasma fibrinogen concentration, factor VII activity, prothrombin time (PT), activated partial thromboplastin time (aPTT) and thromboelastography (TEG) were measured before and 120 minutes after the completion of ANH. RESULTS: Hb, Hct, platelet, plasma fibrinogen concentration and factor VII activity decreased significantly (P < 0.05) after ANH. Compared with pre-ANH values, only maximal amplitude decreased significantly (P = 0.001) among post-ANH thromboelastographic parameters. CONCLUSIONS: Except maximal amplitude, significant difference were not observed in CI (Coagulation Index) which represents general coagulation state and other thromboelastographic parameters between pre and post ANH. ANH with 20 ml/kg of 6% HES (670/0.75) didn't cause impairment of TEG parameters.

JAK2(V617F) Mutation in Korean Patients with Essential Thrombocythemia / 대한진단검사의학회지

BACKGROUND: Essential thrombocythemia (ET) is thought to reflect transformation of a multipotent hematopoietic stem cell, but its molecular pathogenesis remains obscure. But tyrosine kinase, especially Janus kinase 2 (JAK2), has been implicated in myeloproliferative disorders other than chronic myeloid leukemia. We investigated the frequency of JAK2 mutation and its correlation with other clinicopathologic variables in Korean patients with ET and reactive thrombocytosis (RT). METHODS: JAK2 mutation analysis was performed on genomic DNA from bone marrow aspirates of 24 patients with ET and peripheral blood in 36 patients with RT using allele-specific PCR. RESULTS: JAK2 mutation was detected in 11 patients (46%) among the 24 patients with ET and was not found in 36 patients with RT. In patients with ET, older age and leukocytosis were related with JAK2 mutation without statistical significance (P=0.172 and 0.094, respectively). But this mutation was not correlated with sex, hemoglobin, platelet count, splenomegaly, increased cellularity of bone marrow, bone marrow fibrosis and vascular complications. CONCLUSIONS: The current observation strengthens the specific association between JAK2 mutation and ET. At the diagnosis of ET in Korean patients, identification of JAK2 mutation should be incorporated in the basis for new approaches.

Evaluation of Four Commercial IgG- and IgM-specific Enzyme Immunoassays for Detecting Mycoplasma pneumoniae Antibody: Comparison with Particle Agglutination Assay

Diagnosis of Mycoplasma pneumoniae infection is important due to its variable clinical manifestations and absence of response to beta-lactams. Introduction of enzyme immunoassays (EIAs) for serologic diagnosis of M. pneumoniae has made it possible to separate the analyses of specific IgG and IgM antibodies. We compared four different commercial EIAs, ImmunoWELL IgG, IgM (GenBio), Medac IgG, IgA, IgM (Medac), Platelia IgG, IgM (Sanofi Pasteur), and Ridascreen IgG, IgA, IgM (r-Biopharm) with indirect particle agglutination assay (PA), Serodia-MycoII (Fujirebio). We tested 91 specimens from 73 pediatric patients (2-17 yr) hospitalized at a tertiary-care hospital between December 2005 and January 2006. The measurements of IgM EIAs were correlated with PA titers (Spearman's correlation coefficient, from 0.89 to 0.92) with high concordance rates, ranging from 82.4% to 92.3%. However, some negative IgM-EIA results in PA-positive specimens indicated that serial samplings with convalescent sera would be necessary to confirm M. pneumoniae infection.

Detection of 12 Respiratory Viruses with Two-set Multiplex Reverse Transcriptase-PCR Assay Using a Dual Priming Oligonucleotide System / 대한진단검사의학회지

BACKGROUND: We intended to evaluate the diagnostic usefulness of a multiplex reverse transcriptase- PCR (mRT-PCR) assay kit under dual priming oligonucleotide system (DPO) for the childhood acute respiratory tract infections. METHODS: Two hundred nasopharyngeal aspirates were taken from children < or = 5 yr old admitted due to acute respiratory infections in 2004. Direct fluorescent antibody (FA) assays were performed with fresh specimens; then, mRT-PCRs for the detection of 12 respiratory viruses (Seeplex RV detection kit, SeeGene, Seoul, Korea) were tested with frozen specimens. RESULTS: FA assays for five common respiratory viruses showed positive results in 66 patients (33.0%), while mRT-PCR detected causative viruses in 112 patients (56.0%), including 16 co-infected cases (8.0%). A total of 129 viruses were identified: respiratory syncytial virus A/B (38.0%/7.8%), influenza virus A/B (10.1%/5.4%), parainfluenza virus 1/2/3 (7.0%/3.1%/7.8%), coronavirus 229E or NL63 (6.2%), human metapneumovirus (4.7%), adenovirus (4.7%), rhinovirus (3.9%), and coronavirus OC43 (1.6%). CONCLUSIONS: DPO-based mRT-PCR was found as a sensitive tool for the detection of the viruses that cause childhood respiratory infections. Clinical significances of the agents detected by mRTPCR need further evaluations.

Comparison of 3 Automated Immunoassays for Hepatitis B Surface Antigen / 대한진단검사의학회지

BACKGROUND: Hepatitis B surface antigen (HBsAg) is one of the most important serological markers used to diagnose hepatitis B virus (HBV) infection. Automated immunoassays have been developed, meeting the current clinical requirement of HBsAg assays over the years. This study was performed to determine the degree of agreements between 3 kinds of HBsAg assay systems. METHODS: Serum samples from 425 patients were assayed by the HBsAg assay systems of Elecsys (Roche Diagnostics, Germany), ADVIA Centaur (Bayer Diagnostics, USA), and AxSYM (Abbott Laboratories, USA). RESULTS: The concordance rates among the 3 assays were 100%. A total of 249 (58.6%) specimens were positive, and their index values showed a weak correlation between the 3 assays; nevertheless, positive specimens with low levels (<10) of index values in one system also presented low values in other systems, and all of them were confirmed by neutralization assays. CONCLUSIONS: The 3 automated HBsAg assay systems presented a high level of concordance.

Comparison of Two Enzyme Immunoassays for Clostridium difficile Toxin A / 대한진단검사의학회지

BACKGROUND: Clostridium difficile is one of the most important pathogens responsible for nosocomial diarrhea. The disease is mediated by two toxins, designated as A and B; therefore, identification of the toxins is important for diagnosis. However, culture or cytotoxin assay are not easily done because of tedious procedures. Instead, toxin A immunoassay is widely used. We evaluated two different enzyme immunoassays (EIA) for C. difficile toxin A and compared them with culture and PCR results. METHODS: A total of 65 stool specimens were examined for toxin A using enzyme linked fluorescent immunoassay (ELFA, VIDAS CD II, Bio-Merieux, France) and enzyme linked immunosolvent assay (ELISA, C.DIFFICILE TOX A II, TECHLAB, USA ) and were also cultured for C. difficile using cycloserine cefoxitine fructose agar. We amplified toxin A and B genes using primers NK9-NK 11 and NK104-NK105, respectively, in 23 C. difficile isolates. RESULTS: The concordance rate between ELFA and ELISA was 76.9%. The sensitivity and specificity of the ELFA and ELISA based on the culture and PCR results for toxin A gene were 84.6%/98.1% and 84.6%/67.3%. Positive and negative predictive values were 91%/96.2% in VIDAS and 78.0%/ 94.6% in TECHLAB. The positive rates of toxin B genes were 100%, 83.3% and 50% in toxin A positive, variant and negative strains, respectively. CONCLUSIONS: The sensitivities of the ELFA and ELISA for toxin A were the same, but specificity and positive predictive value of the ELFA were higher than those of the ELISA. PCR or EIA method detecting both toxin A and toxin B is strongly recommended, because the variant strains (toxin A negative and toxin B positive) of C. difficile may be more prevalent than were anticipated in Korea.