The experience and reflections of GC labs as an independent clinical laboratory to the COVID-19 pandemic in South Korea.

BACKGROUND: Amid the COVID-19 pandemic, extensive testing was undertaken by independent clinical laboratories (ICLs), yet limited research exists on this matter. Drawing from Green Cross Laboratories (GC Labs)' pandemic response experience, this study seeks to offer insights for preparation for the next pandemic. METHODS: This retrospective study analyzed the outcomes of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (SARS-CoV-2 rRT PCR) tests administered by GC Labs for COVID-19 diagnosis, upon request by different organizations, between February 2020 and April 2022. The distribution of institutions that requested the tests, the type of tests, and the positive rate were analyzed. We investigated resource allocation details. RESULTS: ICLs were responsible for conducting 85.6% of all tests carried out under South Korea's COVID-19 testing policy during the pandemic. The availability of free testing regardless of symptoms led to a significant increase in the use of pooled tests, which accounted for more than 80% of all tests conducted after August 2021. The gender and age distribution of COVID-19 cases nationwide and GC Labs' positive cases were similar. When we analyzed the positive rate by requesting organizations during the COVID-19 pandemic, despite an overall nationwide positivity rate of 35%, high-risk facilities exhibited a positivity rate of less than 5% by maintaining preemptive testing. The most notable increase in resources during the pandemic was seen in human resource input. CONCLUSIONS: South Korea's ICLs were able to conduct large volumes of testing during the COVID-19 pandemic because of their logistics and computer systems, scalable testing space, and trained testing personnel. They also had the flexibility to bring in additional resources to expand testing capacity because they are specialized testing organizations. Hence, ICLs could execute the pooled test that the government had introduced for extensive general population screening. The preemptive periodic testing of high-risk populations kept the positive rate much lower than in the general population. This study's findings will aid in refining mass testing-based policies for the next pandemic.

Different interpretations of inconclusive results of SARS-CoV-2 real-time RT PCR.

We investigated whether inconclusive results could be interpreted differently depending on the situation. First, data from retesting of the initial samples from subjects without a confirmed COVID-19 history were analyzed. And by analyzing the results of consecutive tests with new specimens after receiving inconclusive results between arrivals and locals for 2 periods. As a result, 179 of 219 cases (81.7%) showed still inconclusive or weakly positive results. If contamination is well controlled in a general laboratory, the effectiveness of retesting with the same sample is limited. The rate of the subsequently positive patient was significantly higher in locals than in arrivals and periods with a higher positive rate. The inconclusive results could be interpreted differently depending on the epidemiologic background and the positive rate at that time.

Seroreactivity to Coxiella burnetii in an Agricultural Population and Prevalence of Coxiella burnetii Infection in Ticks of a Non-Endemic Region for Q Fever in South Korea.

Coxiella burnetii infects humans and wild and domesticated animals. Although reported cases on Jeju Island, off the coast of South Korea, are rare, the region is considered to have a high potential for Q fever. We investigated the seroprevalence of antibodies to C. burnetii in 230 farmers living in ten rural areas on Jeju Island between January 2015 and December 2019. Blood samples were collected and examined for C. burnetii Phase I/II IgM and IgG antibodies. Trained researchers collected ticks from rural areas. Clone XCP-1 16S ribosomal RNA gene sequencing was performed to identify Coxiella species from the collected ticks. The overall seroprevalence of antibodies to C. burnetii in farmers was 35.7%. The seroprevalence was significantly higher in fruit farmers. Of the collected ticks, 5.4% (19/351) of the Haemaphysalis longicornis ticks harbored C. burnetti. A high seroprevalence of antibodies to C. burnetii was observed in this region of Jeju Island, confirming that C. burnetti is endemic. Physicians should thus consider Q fever in the differential diagnosis of patients that present with acute fever after participating in outdoor activities.

Cryopreservation of Genotyped ABO Subgroup RBCs for Quality Assurance of ABO Grouping Reagents.

BACKGROUND: Quality assurance of newly developed or manufactured blood grouping reagents with reagent red blood cells (RBCs) is crucial in the process of product approval by governmental agency. However, RBCs with rare blood group are not easily available in the fresh state. We investigated the feasibility of cryopreserved and genotyped ABO subgroup RBC reagents for quality assurance purpose. METHODS: We obtained RBCs from 10 volunteers with ABO subgroup phenotypes. The ABO genotypes and alleles were analyzed by the sequencing of ABO exon 6 and 7. Using the 40% wt/vol high-glycerol method, RBC units were cryopreserved as reagent RBCs into separate cryovials at -80°C. The potency titrations were performed before and after cryopreservation for 6 months and 2 years to evaluate the stability of ABO antigens. RESULTS: ABO genotypes of cryopreserved RBCs were cis-AB01/O01 (n=2), cis-AB01/B101 (n=1), Aw10/B101 (n=2), A201/A201 (n=1), A205/B101 (n=1), A102/B112 (n=1), and A101/B306 (n=1). These ABO subgroup alleles are exclusively present in East-Asian population except for the known ABO*A201 allele. The potency titers of cryopreserved RBCs were not significantly different between pre-freezing and post-freezing. CONCLUSIONS: The national performance evaluation of ABO blood grouping reagents could be performed with cryopreserved and genotyped reagent RBCs.

Hemoglobin assay in anemic patients with a photothermal spectral-domain optical coherence reflectometric sensor.

BACKGROUND: We recently introduced an optical sensor, termed photothermal spectral-domain optical coherence reflectometer (PT SD-OCR), capable of direct measurement of hemoglobin concentration ([Hb]) without chemicals and pre-processing of blood. PT SD-OCR measures [Hb] by quantifying refractive index changes of blood samples due to photothermal effect under the irradiation of 532-nm light. We evaluated diagnostic accuracy and precision of PT SD-OCR in anemic patients. METHODS: We used PT SD-OCR to measure [Hb] in 50 anemic patients, and examined its accuracy against a hematology analyzer (ADVIA 2120i, Siemens AG). Its precision was assessed by examining the SD and CV based on 20 repeated measurements on 3 blood samples. Its performance was also compared with a hemoglobinometer (HemoCue 201+, HemoCue). RESULTS: The PT SD-OCR demonstrated good correspondence with the hematology analyzer with a Pearson's correlation coefficient of 0.992 and a bias of -0.055 g/dl. Standard deviation and CV were measured to be <0.25 g/dl and <2.05%. CONCLUSIONS: Simple and chemical-free operation of PT SD-OCR enabled rapid and accurate measurement of [Hb] in anemic patients. The sensor is expected to facilitate clinical procedures related to blood-related disorders in patient care.

Photothermal spectral-domain optical coherence reflectometry for direct measurement of hemoglobin concentration of erythrocytes.

A novel optical detection method for hemoglobin concentration is described. The hemoglobin molecules consisting mainly of iron generate heat upon their absorption of light energy at 532 nm, which subsequently changes the refractive index of the blood. We exploit this photothermal effect to determine the hemoglobin concentration of erythrocytes without any preprocessing of blood. Highly sensitive measurement of refractive index alteration of blood samples is enabled by a spectral-domain low coherence reflectometric sensor with subnanometer-level optical path-length sensitivity. The performance and validity of the sensor are presented by comparing the measured results against the reference data acquired from an automatic hematology analyzer.

Clinical applicability of real-time, prehospital image transmission for FAST (Focused Assessment with Sonography for Trauma).

We evaluated a real-time, prehospital ultrasound image transmission system for use in focused assessment with sonography for trauma (FAST). The wireless, real-time ultrasound image transmission system comprised an ultrasound scanner with a convex abdominal transducer and a notebook computer connected to a 3 G wireless network for video data transmission. In our simulation experiment, ultrasonography was performed by emergency medical technicians (EMTs) on a human body phantom with simulated haemoperitoneum. Transmitted ultrasound video clips were randomly rearranged and presented to emergency physicians to make a diagnosis of haemoperitoneum. A total of 21 ultrasound video clips was used and 13 emergency physicians participated in the study. The sensitivity and specificity were 90.0% (95% Confidence Interval, CI, 83.5-94.6) and 85.3% (95% CI 78.4-90.7) respectively, and the accuracy of detecting abnormal ultrasound results was 87.7% (95% CI 83.8-91.6). Diagnosis of hemoperitonuem in trauma patients by an emergency physician based on the transmitted video images of FAST performed by an EMT is feasible, and has an accuracy of about 88%.

Characteristics of clinical isolates of Acinetobacter genomospecies 10 carrying two different metallo-beta-lactamases.

Acquired metallo-beta-lactamase (MBL) production is an important mechanism of carbapenem resistance. To our knowledge, carriage of two different MBLs has not been described previously in Acinetobacter spp. We present the characteristics of five Acinetobacter isolates carrying two different MBL genes. The species of all five Acinetobacter isolates with two different MBL genes were Acinetobacter genomospecies 10, and bla(IMP-1), bla(VIM-2) and bla(SIM-1) may coexist in this species. Minimum inhibitory concentrations (MICs) of imipenem for all five isolates with two different MBLs were >or=32 microg/mL, whilst those for two segregants that lost both MBLs were 0.5 microg/mL. The presence of MBL gene-carrying integrons with identical structures suggested the easily transferable nature of the elements, whilst instability of the MBL genes indicated potentially erroneous phenotypic and genetic characterisation.

Efficacy and safety of the computed tomography coronary angiography based approach for patients with acute chest pain at an emergency department: one month clinical follow-up study.

To evaluate the safety and efficacy of the computed tomography coronary angiography (CTCA) for evaluation of acute chest pain in real world population, we prospectively enrolled 296 patients with acute chest pain at emergency department (ED) from November 2005 to February 2007. The patients were grouped based on the clinical information and CTCA result. The patients with a low risk profile and no significant coronary stenosis (>50%) in CTCA were discharged immediately (Group 1, n=103). On the other hand, the patients with an intermediate risk profile without significant stenosis were observed in ED for 24 hr (Group 2, n=104). The patients with significant stenosis underwent further coronary evaluation and management accordingly (Group 3, n=89). While no false negative case was found in Group 1, seven cases (6.73%) were found in Group 2, mostly during the observation period. In Group 3, there were 54 (60.67%) cases of acute coronary syndrome including 10 myocardial infarctions. The overall accuracy of CTCA for acute coronary syndrome was 88.5% (sensitivity), 85.1% (specificity), 60.7% (positive predictive value) and 96.6% (negative predictive value). In conclusion, clinical decision based on CTCA is safe and effective for low risk patients. Further validation is needed in patients with intermediate risk profile.

Antibiotic resistance mechanisms of Escherichia coli Isolates from urinary specimens.

BACKGROUND: This study was designed to characterize urinary isolates of Escherichia coli that produce extended-spectrum beta-lactamases (ESBLs) and to determine the prevalence of other antimicrobial resistance genes. METHODS: A total of 264 non-duplicate clinical isolates of E. coli were recovered from urine specimens in a tertiary-care hospital in Busan in 2005. Antimicrobial susceptibility was determined by disk diffusion and agar dilution methods, ESBL production was confirmed using the double-disk synergy (DDS) test, and antimicrobial resistance genes were detected by direct sequencing of PCR amplification products. E. coli isolates were classified into four phylogenetic biotypes according to the presence of chuA, yjaA, and TSPE4. RESULTS: DDS testing detected ESBLs in 27 (10.2%) of the 264 isolates. The most common type of ESBL was CTX-M-15 (N=14), followed by CTX-M-3 (N=8) and CTX-M-14 (N=6). All of the ESBL-producing isolates were resistant to ciprofloxacin. PCR experiments detected genes encoding DHA-1 and CMY-10 AmpC beta-lactamases in one and two isolates, respectively. Also isolated were 5 isolates harboring 16S rRNA methylases, 2 isolates harboring Qnr, and 19 isolates harboring AAC(6')-Ib-cr. Most ESBL-producing isolates clustered within phylogenetic groups B2 (N=14) and D (N=7). CONCLUSION: CTX-M enzymes were the dominant type of ESBLs in urinary isolates of E. coli, and ESBL-producing isolates frequently contained other antimicrobial resistance genes. More than half of the urinary E. coli isolates harboring CTX-M enzymes were within the phylogenetic group B2.

A tandem triplication, trp(1)(q21q32), in a patient with follicular lymphoma: a case study and review of the literature.

A 1q triplication is a rare karyotypic event in hematologic malignancies, with 26 cases of 1q triplication reported in the literature. Although 1q duplication or triplication is present with a high incidence in Burkitt lymphoma and Fanconi anemia, there have been no detailed reports of an association between non-Burkitt type lymphomas and 1q triplication. Presented here is the case of a 69-year-old man with follicular lymphoma (FL) and 1q triplication, with a review of the pertinent literature. The patient was diagnosed with FL with bone marrow involvement; his bone marrow chromosome study revealed 50,XY,trp(1)(q21q32),+3,+add(3)(q21),+7,+9,add(13)(p11.2)[11]/51 approximately 52,idem,+19,+22[8]/46,XY[3]. Review of the Mitelman Database of Chromosome Aberrations in Cancer revealed 7 previous cases of non-Burkitt type lymphoma (including FL) with 1q triplication. On the basis of these eight cases, we conclude that 1q triplication represents a rare secondary genetic event with prognostic significance in patients with FL or other non-Burkitt types of lymphoma. Further studies are needed to investigate these rare 1q triplication in hematologic malignancies.

8p11 myeloproliferative syndrome preceded by t(8;9)(p11;q33), CEP110/FGFR1 fusion transcript: morphologic, molecular, and cytogenetic characterization of myeloid neoplasms associated with eosinophilia and FGFR1 abnormality.

We report a rare case of t(8;9)(p11;q33) in a patient with 8p11 myeloproliferative syndrome (EMS) that was preceded by centrosomal protein 110kDa (CEP110; previously CEP1)/fibroblast growth factor receptor 1 (FGFR1) fusion transcript. A 36-year-old man was brought to Severance Hospital with a nasopharyngeal mass and eosinophilia. Biopsy of the left tonsil and nasopharynx revealed diffuse infiltration of atypical lymphoid cells, and he was diagnosed with precursor T-cell lymphoma with hypereosinophilic syndrome. Two months later, chromosome study revealed a 46,XY,t(8;9)(p11;q33) karyotype, and the CEP110/FGFR1 fusion transcript was detected by reverse transcription-polymerase chain reaction (RT-PCR) in both this and the previous bone marrow specimen. Timely molecular and cytogenetic tests are of value for diagnosis and treatment of the newly classified "myeloid neoplasms associated with clonal eosinophilic disorders" (according to 2008 World Health Organization criteria).

[Evaluation of the Abbott Cell-Dyn Sapphire hematology analyzer].

BACKGROUND: The performance of Cell-Dyn Sapphire (Abbott Diagnostic, USA) was compared to the Bayer Advia 2120 (Bayer Diagnostics, USA), Sysmex XE-2100 (Sysmex Corporation, Japan), and reference microscopy. METHODS: Three hundred samples for routine CBC and WBC differentials were randomly chosen for a comparison analysis. The Cell-Dyn Sapphire system was evaluated according to the linearity, imprecision, inter-instrument correlations, and white blood cell differential. RESULTS: The CBC parameters (WBC, RBC, hemoglobin and platelet) showed a significant linearity with correlation coefficients greater than 0.99 (P<0.0001). Coefficients of variation (CV) for within-run and differential count of WBC were less than 5% except for Total CV for monocytes, eosinophils, and basophils and within-run CV for low valued eosinophils. The correlation coefficients with manual count were lower in monocytes, eosinophils, and basophils than in neutrophils and lymphocytes. The correlation with other hematology anlayzers was significant exclusive of basophils. CONCLUSIONS: These results demonstrate that the Cell-Dyn Sapphire has a good linearity, an acceptable reproducibility, a minimal carryover, and a comparable performance with the sysmex XE-2100 and Advia 2120.