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Background Newborn screening for congenital adrenal hyperplasia (CAH) has benefits with a high adoption rate worldwide. It also has problems of high false positives, which can cause stress to the patient’s family with economic losses and unnecessary visits of newborns to hospitals. Therefore, we investigated the influence of birth weight (BW), gestational age (GA), and GA with sampling time on 17-hydroxyprogesterone (17-OHP) concentration and attempted to establish the 17-OHP cutoff values in preterm, low birth weight (LBW), and sick newborns. Methods Newborns (n=1,071) born between October 2020 and January 2022 were screened for CAH. Samples from neonates were collected on filter paper with the heel prick method. 17-OHP concentration was measured by time-resolved immunofluorescence with an AutoDELFIA Neonatal 17-hydroxyprogesteron kit and grouped in relation to BW, GA, and GA with sampling time. Results The median age of newborns at neonatal sample collection was 6 days. 17-OHP concentration showed a statistically significant negative correlation with BW (r=−0.488, p Conclusions This study presents new 17-OHP cutoff values for preterm, LBW, and sick newborns. These data in our laboratory can be used as a reference by other laboratories for establishing new cutoff criteria to help lower the high recall rate and reduce unnecessary follow-up tests.

The selective leukoreduction protocol (SLP) is limited in that patients who require it can be overlooked. We estimated SLP compliance (SLPC) using the Observational Medical Outcomes Partnership common data model (CDM).Patients were classified into eight groups: pre- and post-hematology disease (A and B), pre- and post-solid organ transplantation (C and D), solid cancer (E), immunodeficiency (F), anticancer therapy (G), and cardiovascular surgery (H). We examined the red blood cell (RBC) transfusion history from three hospital datasets comprising approximately three million patients over 20 years using CDM-based analysis. SLPC was calculated as the percentage of patients who received only leukoreduced RBCs in total patients transfused RBCs.In total, 166,641 patients from three hospitals were enrolled in this study. From 2001 to 2021, SLPC in all groups, except H, tended to increase, although there were differences among the hospitals. Based on the most recent values (2017-2021), the SLPC in groups A, B, D, and G was maintained at ≥75% until 1,095 days before or after diagnosis or treatment. Groups E, F, and H had50% SLPC one day after diagnosis and treatment.CDM analysis supports the review of large datasets for SLPC evaluation. Although SLPC tended to improve in most patient groups, additional education and monitoring are needed for groups that continue to show low SLPC.

To achieve the measurement reliability of amino acids used as diagnostic markers in clinical fields, establishing a reference measurement system is required, in which certified reference materials (CRMs) are an essential step in the hierarchy of measurement traceability. This study describes the development of dried blood spot (DBS) CRMs for amino acid analysis with complete measurement traceability to the International System of Units (SI). Six essential amino acids─proline, valine, isoleucine, leucine, phenylalanine, and tyrosine─were analyzed using isotope-dilution liquid chromatography-mass spectrometry (ID-MS). For minimizing measurement bias and uncertainty overestimation, whole spots with 50 μL of whole blood were adopted in the certification. The between-spot homogeneities by whole spot sampling were lower than 2.1%. The relative expanded uncertainties of the six amino acids in the developed DBS CRMs were lower than 5.7% at 95% confidence. The certified values are traceable to SI through both gravimetric preparation and the primary method in certification, ID-MS. Comparison among DBS testing laboratories revealed discrepancies between the whole spot and disc sampling methods. The actual sampling volume was accurately estimated by weighing, which revealed the possibility of underestimation in routine DBS testing. The candidate CRMs can support the standardization of DBS testing for amino acids through the qualification and validation of many kinds of measurement procedures to compensate the measurement bias caused by matrix-specific sampling error.

Objective: It is one of the major functions of the clinical laboratory to clearly, accurately, and quickly communicate critical values directly to the patient care providers. Laboratory professionals are often confronted with many obstacles in critical value reporting, including establishing critical values, notifying the critical values to provider, and ensuring that the provider understands the severity of a critical result.Methods: A total of 30 laboratory directors voluntarily answered the questionnaire by e-mail. The questionnaire covered demographic characteristics, establishing and updating critical values lists in clinical chemistry, thresholds of critical values, appropriate timeframes for critical results, notification process, and so on.Results: Of the 30 participating institutions, 12 were general hospitals, three were commercial laboratories, and 15 were tertiary hospitals. The tests included in critical value lists are as follows in order of frequency: potassium, glucose, sodium, total calcium, chloride, ionized calcium, creatinine, magnesium, total bilirubin, phosphorus, pH, and so on. Ten of the 30 institutions notified critical value reports to the patient care providers within 1 hour.Conclusion: This study presents the status of critical value reporting policy in Korean hospitals and a literature review on critical value reporting. In addition, this article provides core components and current regulatory requirements for critical value reporting. Critical value reporting systems should be approved, reviewed, and revised periodically.

The standardization of measurement aims to achieve comparability of results regardless of the analytical methods and the laboratory where analyses are carried out. In this paper, a comparison of results from several immunoassay-based insulin analysis kits is described, and the steps necessary to improve comparability are discussed.Four manual enzyme-linked immunosorbent assay (ELISA) kits produced by Mercodia, Alpco, Epitope Diagnostics, and Abcam, and three automated chemiluminescent (CLIA) insulin assay kits (Siemens Centaur XP, Unicel Dxl800, Cobas e801) were compared by analyzing human serum samples and certified reference materials for human insulin.The seven evaluated assay kits showed substantial discrepancies in the results, with relative standard deviation ranges between 1.7% and 23.2%. We find that the traceability chains and the unit conversion factors are not yet harmonized, and current reference materials for insulin are not applicable for immunoassay-based method validation due to the use of different matrices.The findings suggest the need to fine tune insulin analysis methods, measurement traceability, and any conversion factor used in post-analysis steps in accordance with the necessity for standardization.

BACKGROUND Medical laboratories play a central role in health care. Many laboratories are taking a more focused and stringent approach to quality system management. In Korea, laboratory standardization efforts undertaken by the Korean Laboratory Accreditation Program (KLAP) and the Korean External Quality Assessment Scheme (KEQAS) may have facilitated an improvement in laboratory performance, but there are no fundamental studies demonstrating that laboratory standardization is effective. We analyzed the results of the KEQAS to identify significant differences between laboratories with or without KLAP and to determine the impact of laboratory standardization on the accuracy of diagnostic tests. METHODS We analyzed KEQAS participant data on clinical chemistry tests such as albumin, ALT, AST, and glucose from 2010 to 2013. As a statistical parameter to assess performance bias between laboratories, we compared 4-yr variance index score (VIS) between the two groups with or without KLAP. RESULTS Compared with the group without KLAP, the group with KLAP exhibited significantly lower geometric means of 4-yr VIS for all clinical chemistry tests (P

Human papillomavirus (HPV) is a major cause of cervical neoplasia development. HPV screening is very important because early treatment can prevent cervical cancer. Omniplex-HPV is a polymerase chain reaction followed by Luminex xMAP bead microarray technology that is designed for detecting 40 HPV genotypes. The aim of this study is to evaluate the analytical and clinical performance of the Omniplex-HPV in comparison with that of the commercially available RFMP (restriction fragment mass polymorphism) HPV PapilloTyper. A total of 2,808 cervical swab specimens were obtained. Of these, only 1799 specimens had a cytology result. A type-specific direct sequencing test was performed using the reference method in case of discrepancies between the two test results. The overall percent agreement (OPA) between Omniplex-HPV and RFMP HPV PapilloTyper was 97.9% (κ=0.84; 95% CI: 0.81-0.88). The positive percent agreement (PPA) and the negative percent agreement (NPA) were 98.0% and 96.2%, respectively. The Omniplex-HPV and RFMP HPV PapilloTyper showed comparable sensitivities (90.2% and 91.9%, respectively) and specificities (91.3% each), while the Omniplex-HPV produced more accurate results and required less turnaround time and labor. The agreement between these two methods was excellent for HPV genotyping (P>0.05; McNemar’s test), and clinical sensitivity, specificity, and odds ratio of the two assays were comparable to the result of cytology tests in identifying high risk HPV. In conclusion, Omniplex-HPV and RFMP HPV PapilloTyper were highly comparable with regard to detection and genotyping analysis of HPV.

We report a case of subcutaneous infection in a 55-yr-old Korean diabetic patient who presented with a cystic mass of the ankle. Black fungal colonies were observed after culturing on blood and Sabouraud dextrose agar. On microscopic observation, septated ellipsoidal or cylindrical conidia accumulating on an annellide were visualized after staining with lactophenol cotton blue. The organism was identified as Exophiala salmonis by sequencing of the ribosomal DNA internal transcribed spacer region. Phaeohyphomycosis is a heterogeneous group of mycotic infections caused by dematiaceous fungi and is commonly associated with immunocompromised patients. The most common clinical manifestations of subcutaneous lesions are abscesses or cystic masses. To the best of our knowledge, this is the first reported case in Korea of subcutaneous phaeohyphomycosis caused by E. salmonis that was confirmed by molecular analysis and identification of morphological characteristics. This case suggests that E. salmonis infections are no longer restricted to fish.

Systemic primary carnitine deficiency (CDSP) is a rare autosomal recessive disorder that presents episodic periods of hypoketotic hypoglycemia. The main symptoms of CDSP are skeletal and cardiac myopathy. CDSP is caused by a defect in plasma membrane uptake of carnitine, ultimately caused by the SLC22A5 gene. We report the case of a Korean patient with CDSP. He had an abnormal free carnitine level of 5.56 μmol/L (reference range, RR 10.4~87.1 μmol/L) and a palmitoylcarnitine level of 0.27 μmol/L (RR 0.5~9.7 μmol/L) in a newborn screening test. The patient showed an ammonia level of 129.4 ug/dL (RR, 25~65 ug/dL), a lactate level of 4.5 mmol/L (RR, 0.5-2.2 mmol/L), and a free carnitine level of 10.3 μmol/L (RR, 36-74 μmol/L) in blood. After PCR-sequencing analysis of the SLC22A5 gene, the patient was found to be a compound heterozygote for c.506GA (p.R169Q) and c.1400CG (p.S467C) mutations. These missense mutations are reported previously. The patient was started on L-carnitine supplement after CDSP diagnosis. The patient was treated with L-carnitine to reach a normal free carnitine level and has remained asymptomatic up to the current age of 21 months. The plasma free carnitine level normalized to 66.6 μmol/L at 4 weeks after treatment. To the best of our knowledge, this is the first report of a CDSP patient confirmed by molecular genetic investigation.