Purpose: To report a case of retrobulbar optic neuritis after COVID-19 infection.Case summary: A 20-year-old Korean man, without any previous relevant medical history, presented with sudden blurred vision in the left eye that began 6 days after a COVID-19 infection. At his initial visit, the best-corrected visual acuity in the left eye was counting fingers at 30 cm. The pupil showed a grade 2 relative afferent pupillary defect. The fundus exam was normal in both eyes. In the visual evoked potential (VEP) exam, the P100 amplitude of the left eye was decreased and delayed. Orbit magnetic resonance imaging showed asymmetric enlargement and mild enhancement in the left optic nerve. No other lesions were observed around the optic nerve. Steroid pulse therapy was started after a diagnosis of retrobulbar optic neuritis. After 1 month, the patient’s visual acuity had improved to 1.0 in the left eye. The relative afferent pupillary defect and visual field defect disappeared. On VEP, the P100 amplitude recovered, and the delay disappeared. Conclusions Retrobulbar optic neuritis is a possible neuro-ophthalmological complication of COVID-19 infection. In such cases, high-dose steroid pulse therapy may be helpful, as in the treatment of other forms of optic neuritis.

Purpose: To determine subjective symptoms and medical history of patients with intermittent exotropia in a large study population. Methods: The Korean Intermittent Exotropia Multicenter Study (KIEMS) is a nationwide, observational, cross-sectional, multicenter study conducted by the Korean Association for Pediatric Ophthalmology and Strabismus including 5,385 patients with intermittent exotropia. Subjective symptoms and medical history of patients with intermittent exotropia were extracted by a comprehensive survey based on a self-administered questionnaire according to the study protocol of the KIEMS. Results: The mean age of symptom onset was 5.5 years. The most common symptom reported in patients with intermittent exotropia was photophobia (52.1%), followed by diplopia at near fixation (7.3%) and distance fixation (6.2%). Preterm birth was found in 8.8%, and 4.1% had perinatal complications. A family history of strabismus was present in 14.9%, and 5.5% of patients had a family member who underwent strabismus surgery. Conclusions The KIEMS is one of the largest clinical studies on intermittent exotropia. Intermittent exotropia frequently caused photophobia and diplopia, and patients with a family history was not uncommon.

BACKGROUND: For creatinine measurement, the enzymatic method is known to be more accurate than the Jaffe method; however, the latter is still widely used. We evaluated the performance of the CRE2 reagent (Siemens Healthcare Diagnostics Inc., USA), which uses a modified Jaffe method. METHODS: Three quality control standards were used for precision evaluations of CRE2 on Dimension VISTA 500 instrument (Siemens). Moreover, the linearity and carryover characteristics were assessed. Sixty-eight creatinine results obtained using the CRE2 and ECREA (enzymatic) reagents (Siemens) were compared with those obtained using the L-CRE (enzymatic) reagent (Shinyang Diagnostics, Korea). The accuracy of CRE2, ECREA, and L-CRE was evaluated using a standard reference material. RESULTS: The CV of within-run (0.7–2.4%), between-run (0.4–1.7%), between-day precision (0.7–0.9%) for three standards, and total CV for medium (1.6%) and high levels (1.3%) satisfied the analytical goal. The linearity for CRE2 was excellent (R2=0.999). Comparisons of CRE2 and ECREA to L-CRE were well correlated (r=0.996 and 0.997, respectively). In comparison with L-CRE, 5 CRE2 results and 15 ECREA results exceeded minimum bias goal (5.1%) in samples with creatinine levels of >1 mg/dL. The carryover rate was −0.04%. In terms of accuracy, the percent bias values of CRE2, ECREA, and L-CRE were 7.4, −6.4, and −3.4, respectively, for low level; and 3.9, −1.5, and 0.7, respectively, for high level. CONCLUSIONS: For creatinine measurements, the CRE2 reagent showed good performance. It can be used in the diagnosis, treatment monitoring, and risk assessment of kidney diseases.
Bias (Epidemiology) ; Creatinine* ; Delivery of Health Care ; Diagnosis ; Indicators and Reagents ; Kidney Diseases ; Methods ; Quality Control ; Risk Assessment

BACKGROUND: Automated systems are used widely for pre-transfusion tests in blood banks, in an attempt to reduce effort and human error. We evaluated the clinical performance of an automated blood bank system, ORTHO VISION (Ortho-Clinical Diagnostics, Switzerland), for blood cross-matching. METHODS: Saline cross-matching was performed for 93 tests using 56 samples. Coombs cross-matching was performed for 400 tests using 166 samples. Saline cross-matching was compared for the automated ORTHO VISION and manual tube methods. Coombs cross-matching was compared for the automated ORTHO VISION and manual column agglutination technique (CAT) methods. The evaluation of 32 antibody-positive samples using the automated ORTHO VISION and manual CAT methods was compared by performing 97 cross-matching tests. Additionally, the ORTHO VISION efficiency and carryover were evaluated. RESULTS: The concordance rate of the saline cross-matching results between the manual method and automated ORTHO VISION was 100%. The concordance rate of coombs cross-matching results between manual CAT and automated ORTHO VISION was 97.9%. The concordance rate of cross-matching for antibody positive samples between manual CAT and the automated ORTHO VISION was 97.9%. Coombs cross-matching was efficient using ORTHO VISION, whereas saline cross-matching was efficient using the tube manual method. CONCLUSIONS: ORTHO VISION showed reliable results for cross-matching and was more efficient than manual CAT for coombs cross-matching. Thus, ORTHO VISION can be used for pre-transfusion tests in blood banks.
Agglutination ; Animals ; Automation ; Blood Banks ; Cats ; Humans ; Methods

BACKGROUND: Analysis of body fluids provides important information for assessing various medical conditions. We aimed to validate the analytical and diagnostic performance of the Sysmex UF-5000 (Sysmex, Japan) system for the analysis of different body fluids. METHODS: Eighty body fluid samples were analyzed using the UF-5000 system in the body fluid mode and light microscopy. Body fluids included ascitic, pleural, and cerebrospinal fluid (CSF), as well as other fluid samples. RESULTS: A comparison between the UF-5000 system and manual counting demonstrated good correlations with regard to red (r=0.6555) and white blood cell (r=0.9666) counts. The UF-5000 system also demonstrated good performance for differential cell counting (r=0.9028). CSF particularly showed a good correlation. CONCLUSIONS: The use of the UF-5000 system for cell counting and differential analysis of body fluid samples might be an effective and automated alternative to chamber counting in laboratory routine analysis, thereby enhancing laboratory workflow and clinical effectiveness.
Automation ; Body Fluids ; Cell Count ; Cerebrospinal Fluid ; Erythrocytes ; Leukocytes ; Methods ; Microscopy ; Treatment Outcome

BACKGROUND: The use of automated systems for pre-transfusion tests is increasing in an attempt to reduce workload and the impact of human errors in blood banks. We evaluated the clinical performance of the automated blood bank systems IH-500 (Bio-Rad Laboratories, Switzerland) and VISION Max (Ortho-Clinical Diagnostics, USA) for ABO-RhD blood typing and unexpected antibody screening. METHODS: ABO-RhD blood typing was performed for 410 samples, and antibody screening was performed for 332 samples, including 15 antibody-positive samples. The results obtained from the two automated instruments were compared with those obtained using manual methods for ABO-RhD blood typing and a semiautomated method (DiaMed-ID system) for antibody screening. Additionally, both instruments were evaluated in terms of concordance rates, sensitivity, and carryover. RESULTS: The concordance rate of the ABO-RhD blood typing results between the manual methods and the two automated instruments was 100%. For antibody screening tests, the concordance rates between the semiautomated method (DiaMed-ID system) and the automated methods were 100% and 99.7% for the IH-500 and VISION Max instruments, respectively. The sole discrepant result was obtained for a sample identified as antibody-positive only on the VISION Max; the antibody was identified as anti-Le(a). The overall sensitivity of the two automated instruments was the same as or higher than that of the semiautomated method. Carryover was not observed in antibody screening. CONCLUSIONS: The IH-500 and VISION Max instruments showed reliable results for ABO-RhD blood typing and unexpected antibody screening, and can be used clinically, with confidence, for pre-transfusion tests in the blood bank.
Automation ; Blood Banks* ; Blood Grouping and Crossmatching* ; Humans ; Mass Screening* ; Methods

BACKGROUND: External quality assessment (EQA) uses a standard deviation index (SDI), based on a peer group, to evaluate laboratory performance. However, evaluations using peer group SDIs often have limited applicability, because they are not statistically valid unless the number of institutions in the same peer group is large. The present study proposes a statistical model for simultaneously evaluating the performance of all participating institutions, as well as the performance of instruments on the market. METHODS: By assuming that proficiency test results were affected by the manufacturer, the instrument, and the institution, the effects of those factors were estimated using a linear mixed model. We used these effect estimates to calculate manufacturer, instrument, and institution SDIs. Using simulation, we evaluated the false positive rates and efficiencies of the proposed linear mixed model. RESULTS: Simulations showed that the linear mixed model empirical type I error rates preserved the nominal significance level. This model was also more statistically efficient than the peer group SDI. Rates of unacceptability were lower when using institution SDI than they were when using peer group SDI. Additional outliers that could not be evaluated using the current system were detected by the institution SDI statistic. The instrument SDI statistic detected outliers among different instrument groups. CONCLUSIONS: Institution and instrument SDIs are robust and efficient tools for EQA, and they can replace the currently used system of peer group SDI.
Laboratory Proficiency Testing ; Models, Statistical ; Peer Group

No abstract available.
*Aneuploidy ; Bone Marrow/pathology ; Chromosomes, Human, Pair 21 ; Down Syndrome/*complications ; Female ; Humans ; Hyperplasia/pathology ; In Situ Hybridization, Fluorescence ; Infant ; Isochromosomes/*genetics ; Karyotype ; Leukemia, Megakaryoblastic, Acute/complications/*diagnosis ; Megakaryocytes/pathology

BACKGROUND: Methotrexate (MTX) is an antifolate antagonist that is widely used for treating various malignancies and non-malignant diseases. MTX levels should be monitored when used in high concentration to determine when to start leucovorin rescue. In this study, we evaluated the analytical performance of the EMIT Methotrexate Assay on a 200FR NEO Chemistry Analyzer (Toshiba Medical System Co., Japan) and compared it with Viva-E Drug Testing System (Siemens Healthcare, Germany). METHODS: According to the Clinical Laboratory and Standards Institute (CLSI) Evaluation Protocol (EP) 5-A2, three concentrations of the Liquichek Therapeutic Drug Monitoring Control (Bio-Rad Laboratories, USA) were analyzed twice a day for 20 days to monitor assay precision. The 200FR NEO and Viva-E instruments were compared using 40 patients' sera, according to CLSI EP9-A2. The linearity and carry-over rate were also evaluated. RESULTS: Between-run CVs for low-, medium-, and high-level controls were 4.9%, 0.9%, and 2.0%, respectively, whereas between-day CVs for low-, medium-, and high-level controls were 8.1%, 1.3%, and 3.5%, respectively. In the linearity test, the coefficient of determination (R2) was 0.98 (0.06-1.92 micromol/L). In the comparison study, R2 was 0.955, showing good correlation between the 200FR NEO and Viva-E instruments. The carry-over rate was 0.9%. CONCLUSIONS: The EMIT assay showed good precision, linearity, and carry-over rate on the Toshiba 200FR. An excellent correlation was observed when comparing results obtained using the Toshiba and Viva-E instruments. In conclusion, the Syva EMIT MTX assay can be readily used for MTX monitoring on the Toshiba 200FR NEO.
Chemistry ; Delivery of Health Care ; Drug Monitoring ; Leucovorin ; Methotrexate*

No abstract available.
Blood Cell Count ; Bone Marrow Cells/metabolism/pathology ; Humans ; Leukemia, Promyelocytic, Acute/complications/*diagnosis/pathology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Multiple Myeloma/complications/*diagnosis/pathology ; Paraproteinemias/diagnosis ; Syndecan-1/metabolism