BACKGROUND: We aimed to determine the major contributing component of metabolic syndrome (MetS) that results in an elevated small dense LDL cholesterol (sdLDL-C) concentration and sdLDL-C/LDL-C ratio. METHODS: Four hundred and forty-seven subjects (225 men; 222 women) with MetS were randomly selected from the Korean Metabolic Syndrome Research Initiatives-Seoul cohort study. Age- and sex-matched healthy controls (181 men; 179 women) were also randomly selected from the same cohort. RESULTS: A comparison of the median values of the sdLDL-C concentration between subgroups, divided according to whether subjects met or did not meet the criteria for each MetS component in patients with MetS, revealed a significant difference in the sdLDL-C concentration only between subgroups divided according to whether subjects met or did not meet the triglyceride (TG) criteria (P<0.05 for each gender). The TG level showed a good correlation with sdLDL-C concentration (correlation coefficients [r]=0.543 for men; 0.653 for women) and the sdLDL-C/LDL-C ratio (r=0.789 for men; 0.745 for women). Multiple linear regression analyses conducted for the MetS group concordantly identified TG as one of the most significant contributors to sdLDL-C concentration (beta=0.1747+/-0.0105, P<0.0001) and the sdLDL-C/LDL-C ratio (beta=6.9518+/-0.3011, P<0.0001). CONCLUSIONS: Among five MetS components, only the abnormal TG level was a differentiating factor for sdLDL-C concentration and sdLDL-C/LDL-C ratio. These results were reproducible in both genders, with or without MetS.
Adult ; Case-Control Studies ; Cholesterol, LDL/*blood ; Cohort Studies ; Female ; Humans ; Hypertriglyceridemia/*complications/diagnosis ; Linear Models ; Male ; Metabolic Syndrome X/*complications/diagnosis ; Middle Aged ; Risk Factors ; Triglycerides/blood

Rapid influenza diagnostic test (RIDT) is widely used for the diagnosis of influenza owing to its simplicity and convenience of use. This study aimed to evaluate the performance of a new RIDT, SD Standard F influenza A/B FIA (SD Biosensor, Inc., Korea) (Standard F) and compare its performance with BD Veritor Flu A+B (Veritor), using the results of real-time reverse transcription PCR (rRT-PCR) analysis as the standard for reference. On comparing the results obtained from both the RIDTs and rRT-PCR qualitatively, it was found that the Veritor and Standard F assays have the sensitivity of 65.6% (21/32) and 71.9% (23/32), respectively, for the detection of influenza A with a specificity of 100.0% (68/68). Additionally, both the assays demonstrated a sensitivity of 66.7% (12/18) and specificity of 100.0% (68/68) for the detection of influenza B. The cutoff index (COI) value of the fluorescence color intensity from the Standard F assay, displayed on the device along with the qualitative results, indicated a negative correlation with the Ct value from rRT-PCR for both influenza A and B (P<0.001). The sensitivity of the new RIDT for the detection of influenza was comparable with that of the Veritor assay and the new RIDT could be used as a substitute for existing RIDTs by providing additional information to predict the approximate viral burden of influenza.

BACKGROUND: Recently, a new automated chemistry analyzer, Atellica CH930 (Siemens, Germany), was introduced. It automatically measures internal quality control (QC) materials according to a pre-determined schedule. For this purpose, the instrument has space for storage of QC materials. We evaluated the analytical performance of chemistry items by using the Atellica system. METHODS: The precision of 29 items was evaluated with three levels of QC materials with two storage methods. We stored the QC materials in the dedicated storage space in the instrument during the precision evaluation period. In addition, we aliquoted and stored the materials in the refrigerator, and then loaded the material in a timely manner. Linearity, carry-over, and agreement with current methods were also evaluated. RESULTS: The within-laboratory coefficient of variation (CV) of most items, except for total CO2 (tCO2), was within 5.0% in both QC storage methods without significant differences in CV between storage methods. The CV of tCO2 was 5.2%, 5.8%, and 5.1% at three different levels when the QC materials were stored in a dedicated space in the instrument. The linearity was acceptable, showing <5% nonlinearity. Although good agreement was observed for most items, some items, such as calcium, total bilirubin, aspartate transaminase, and chloride, showed unequivalent results. CONCLUSIONS: Atellica CH930 showed acceptable precision, linearity, and agreement in routine chemistry items. The automatic QC function using the storage device has no problem with stability or precision. It can reduce the manual process, allowing technicians to focus on reviewing the QC results and reporting reliable results.
Appointments and Schedules ; Aspartate Aminotransferases ; Bilirubin ; Calcium ; Chemistry ; Quality Control

Procalcitonin (PCT) is a useful bacterial infection biomarker with the potential for guiding antibiotic therapy. We evaluated the concordance of three automated PCT immunoassays: Kryptor (BRAHMS GmbH, Hennigsdorf, Germany), Atellica IM 1600 (Siemens Healthcare Diagnostics, Munich, Germany), and Cobas e801 (Roche Diagnostics, Mannheim, Germany). In 119 serum samples with a PCT concentration < 5.00 μg/L, Kryptor (reference assay) was compared with the other two immunoassays by Spearman’s rank correlation, regression analysis, and concordance at two antibiotic stewardship medical decision points: 0.25 and 0.50 μg/L. The Atellica IM 1600 and Cobas e801 results showed high correlations with those of Kryptor, with correlation coefficient (ρ) values of 0.97 and 0.99, respectively. However, negative biases were observed in both immunoassays (slope/y-intercept: 0.75/–0.00 for Atellica IM 1600; 0.88/–0.01 for Cobas e801). Atellica IM 1600 and Cobas e801 demonstrated excellent concordance with Kryptor at both medical decision points, with linearly weighted κ values of 0.90 and 0.92, respectively, despite discrepancies, which were more prominent at the 0.25 μg/L medical decision point. Based on these biases and discrepancies, the alternate use of different PCT immunoassays in repeat examinations is inadvisable. Standardization is required before comparing the results of different PCT immunoassays.

Parvovirus B19 infection is known to cause chronic anemia in immunocompromised hosts, including organ transplant recipients. We report the first case of liver transplant recipient with parvovirus B19-induced pure red cell aplasia in Korea. A 57-yr-old female patient with hepatocellular carcinoma due to hepatitis C virus received a liver transplantation. Two months later, anemia developed and she received periodic red blood cell transfusions. However, chronic anemia persisted and bone marrow examination was performed 8 months after transplantation. Bone marrow aspiration smears showed markedly reduced erythroid precursors with atypical giant pronormoblasts and nuclear remnants with viral inclusions, and characteristic lantern cells were observed in biopsy sections. In addition, parvovirus B19 DNA PCR was positive. She was diagnosed as parvovirus B19-induced pure red cell aplasia and her anemia was improved following intravenous immunoglobulin therapy.
Blood Transfusion ; Bone Marrow/pathology ; Carcinoma, Hepatocellular/etiology/therapy ; DNA, Viral/analysis ; Female ; Hepatitis C/complications/diagnosis ; Humans ; Immunocompromised Host ; Immunoglobulins/therapeutic use ; Liver Neoplasms/etiology/therapy ; Liver Transplantation ; Middle Aged ; Parvoviridae Infections/complications/*diagnosis ; *Parvovirus B19, Human/genetics ; Red-Cell Aplasia, Pure/*diagnosis/therapy/virology

Li-Fraumeni syndrome (LFS) is a rare, inherited syndrome associated with increased risk of various early-onset tumors. Since the introduction of classic LFS criteria, various criteria have been proposed to include patients with incomplete LFS features, which make up Li-Fraumeni-like syndromes (LFL). Germline missense mutations of TP53 are the primary cause of LFS and LFL. Mutations mostly reside in the DNA-binding domain of the gene and have a dominant-negative effect (DNE) over alternate wild-type alleles. Germline TP53 mutation c.566C>T results in the missense mutation GCC (Ala) to GTC (Val) at codon 189 (A189V) and has been reported in a case of multiple primary colon tumors. Herein we report a second case of the same mutation in a breast cancer patient, who has familial history of late-onset malignancies. Due to the relatively late onset of malignancies, neither case fulfils previously defined criteria for the syndrome. Mutational analysis for breast tissue in this patient showed a loss of heterozygosity. These clinical features may suggest a relatively weak DNE of A189V compared to other TP53 mutations, and in silico predictions and in vitro findings of the function of A189V mutant protein are conflicting. Considering the increased risk of malignancies and the therapeutic implications for patients who have a TP53 mutation, care must be taken when treating those who are suspected of possessing cancer-prone traits due to TP53 mutation, especially when there is a family history of late-onset cancer with low penetrance.
Adolescent ; Adult ; Breast Neoplasms/complications/*diagnosis/therapy ; Combined Modality Therapy ; Exons ; Female ; Genotype ; Heterozygote ; Humans ; Li-Fraumeni Syndrome/complications/*diagnosis/therapy ; Middle Aged ; Multimodal Imaging ; Mutation, Missense ; Pedigree ; Sequence Analysis, DNA ; Tumor Suppressor Protein p53/genetics ; Young Adult

Li-Fraumeni syndrome (LFS) is a rare, inherited syndrome associated with increased risk of various early-onset tumors. Since the introduction of classic LFS criteria, various criteria have been proposed to include patients with incomplete LFS features, which make up Li-Fraumeni-like syndromes (LFL). Germline missense mutations of TP53 are the primary cause of LFS and LFL. Mutations mostly reside in the DNA-binding domain of the gene and have a dominant-negative effect (DNE) over alternate wild-type alleles. Germline TP53 mutation c.566C>T results in the missense mutation GCC (Ala) to GTC (Val) at codon 189 (A189V) and has been reported in a case of multiple primary colon tumors. Herein we report a second case of the same mutation in a breast cancer patient, who has familial history of late-onset malignancies. Due to the relatively late onset of malignancies, neither case fulfils previously defined criteria for the syndrome. Mutational analysis for breast tissue in this patient showed a loss of heterozygosity. These clinical features may suggest a relatively weak DNE of A189V compared to other TP53 mutations, and in silico predictions and in vitro findings of the function of A189V mutant protein are conflicting. Considering the increased risk of malignancies and the therapeutic implications for patients who have a TP53 mutation, care must be taken when treating those who are suspected of possessing cancer-prone traits due to TP53 mutation, especially when there is a family history of late-onset cancer with low penetrance.
Adolescent ; Adult ; Breast Neoplasms/complications/*diagnosis/therapy ; Combined Modality Therapy ; Exons ; Female ; Genotype ; Heterozygote ; Humans ; Li-Fraumeni Syndrome/complications/*diagnosis/therapy ; Middle Aged ; Multimodal Imaging ; Mutation, Missense ; Pedigree ; Sequence Analysis, DNA ; Tumor Suppressor Protein p53/genetics ; Young Adult

The accuracy-based lipid (ABL) proficiency testing (PT) program was started in 2016 by the Korean External Quality Assessment Service to minimize the matrix effect. We analyzed 3 years of the program. We made or purchased six kinds of commutable frozen sera based on the Clinical and Laboratory Standards Institute 37A guideline and distributed it in two rounds per year from 2016 to 2018. We obtained reference values for levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), total glycerides, and triglycerides in each fresh frozen pool at the reference-measurement laboratories. We evaluated the average percent bias of the participating laboratories based on the National Cholesterol Education Program (NCEP) bias limit. The number of participating laboratories evaluating TC, HDLC, LDLC, total glycerides, and triglycerides increased from 164 to 223, 163 to 223, 158 to 214, 98 to 139, and 61 to 82, respectively. The average percent bias of all participating laboratories for TC, HDLC, LDLC, total glycerides, and triglycerides was +0.14%, −0.54%, +2.9%, −1.08%, and −1.32%, respectively. The average percent bias exceeded the NCEP bias limit only once or twice for TC, HDLC, and total glycerides but frequently for LDLC (eight out of 18 pools). The manufacturer-specific bias estimation report seemed useful for traceability. Although the average percent bias of participating laboratories for TC, HDLC, LDLC, total glycerides, and triglycerides was mostly within the bias limit provided by NCEP, cases of bias limit exceeding the NCEP bias limit occurred occasionally, especially for LDLC during the 3 years of the ABL PT program in Korea, suggesting that ABL PT can be used to keep maintaining traceability.
Bias (Epidemiology) ; Cholesterol ; Education ; Glycerides ; Korea ; Laboratory Proficiency Testing ; Lipoproteins ; Reference Values ; Triglycerides

Appropriate reference intervals of serum insulin-like growth factor I (IGF-I) is important for diagnosing and monitoring patients with growth hormone-related diseases. To establish reference intervals, adult individuals (n=1,334, 680 men and 654 women) were divided into six age groups (20–29, 30–39, 40–49, 50–59, 60–69, ≥70). Serum IGF-I was measured by chemiluminescence immunoassay (Liaison). Concordance of patient classification based on reference intervals, manufacturer’s intervals, and standard deviation score (SDS) was evaluated. New reference intervals had higher upper and lower limits than those specified by the manufacturer. The agreement between classification using new reference interval and the manufacturer’s reference interval, and that using new reference interval and SDS was 75.0% (weighted kappa, 0.17), 91.9% (weighted kappa, 0.51) in men and 91.0% (weighted kappa, 0.41), 92.5% (weighted kappa, 0.53) in women, respectively. Reference intervals should be established not only based on age and sex, but also on ethnicity and assay method.