Quantitative Evaluation of the Real-World Harmonization Status of Laboratory Test Items Using External Quality Assessment Data.

Background: In recent decades, the analytical quality of clinical laboratory results has substantially increased because of collaborative efforts. To effectively utilize laboratory results in applications, such as machine learning through big data, understanding the level of harmonization for each test would be beneficial. We aimed to develop a quantitative harmonization index that reflects the harmonization status of real-world laboratory tests. Methods: We collected 2021-2022 external quality assessment (EQA) results for eight tests (HbA1c, creatinine, total cholesterol, HDL-cholesterol, triglyceride, alpha-fetoprotein [AFP], carcinoembryonic antigen [CEA], and prostate-specific antigen [PSA]). This EQA was conducted by the Korean Association of External Quality Assessment Service, using commutable materials. The total analytical error of each test was determined according to the bias% and CV% within peer groups. The values were divided by the total allowable error from biological variation (minimum, desirable, and optimal) to establish a real-world harmonization index (RWHI) at each level (minimum, desirable, and optimal). Good harmonization was arbitrarily defined as an RWHI value ≤ 1 for the three levels. Results: Total cholesterol, triglyceride, and CEA had an optimal RWHI of ≤ 1, indicating an optimal harmonization level. Tests with a desirable harmonization level included HDL-cholesterol, AFP, and PSA. Creatinine had a minimum harmonization level, and HbA1c did not reach the minimum harmonization level. Conclusions: We developed a quantitative RWHI using regional EQA data. This index may help reflect the actual harmonization level of laboratory tests in the field.

Preoperative prediction of metastatic pheochromocytoma and paraganglioma using clinical, genetic, and biochemical markers: A cohort study.

BACKGROUND: The prevalence of metastatic pheochromocytoma and paraganglioma (PPGL) is approximately 15%-20%. Although there are indicators to assess metastatic risks, none of them predict metastasis reliably. Therefore, we aimed to develop and validate a scoring system using clinical, genetic, and biochemical risk factors to preoperatively predict the metastatic risk of PPGL. METHODS: In the cross-sectional cohort (n = 180), clinical, genetic, and biochemical risk factors for metastasis were identified using multivariate logistic regression analysis, and a novel scoring system was developed. The scoring system was validated and compared with the age, size of tumor, extra-adrenal location, and secretory type (ASES) score in the longitudinal cohort (n = 114). RESULTS: In the cross-sectional cohort, pseudohypoxia group-related gene variants (SDHB, SDHD, or VHL), methoxytyramine >0.16 nmol/L, and tumor size >6.0 cm were independently associated with metastasis after multivariate logistic regression. Using them, the gene variant, methoxytyramine, and size of tumor (GMS) score were developed. In the longitudinal cohort, Harrell's concordance index of the GMS score (0.873, 95% confidence interval [CI]: 0.738-0.941) was higher than that of the ASES score (0.713, 95% CI: 0.567-0.814, p = 0.007). In the longitudinal cohort, a GMS score ≥2 was significantly associated with a higher risk of metastasis (hazard ratio = 25.07, 95% CI: 5.65-111.20). A GMS score ≥2 (p < 0.001), but not ASES score ≥2 (p = 0.090), was associated with shorter progression-free survival. CONCLUSION: The GMS scoring system, which integrates gene variant, methoxytyramine level, and tumor size, provides a valuable preoperative approach to assess metastatic risk in PPGL.

Impact of Academia-Government Collaboration on Laboratory Medicine Standardization in South Korea: analysis of eight years creatinine proficiency testing experience.

OBJECTIVES: To evaluate the performance of the Academia-Government Collaboration for Laboratory Medicine Standardization in Korea (KR-STDZN) based on data from KR-STDZN proficiency testing (KR-STDZN-PT) for creatinine over eight years (2015-2022). METHODS: We used KR-STDZN-PT data of creatinine tests from 2015 to 2022. Acceptance of the participating institutions' test results was assessed by calculating the acceptance performance as absolute bias (absBias%), total coefficient of variance (tCV%), and total error (TE%) for each sample using six measurements from each institution and true values of each reference material. The test result was considered acceptable when absBias%, tCV%, and TE% were <5.10, <3.20, and <11.40 %, respectively. The proportion of acceptable institutions among all participating institutions in each round was defined as the acceptance rate. Improvements in absBias%, tCV%, and TE% were analyzed using creatinine concentration ranges in samples. RESULTS: The number of participating institutions increased from 2015 to 2017 but remained consistent since 2018. The acceptance rates for absBias% and TE% increased from 52.2 and 77.6 %, in 2015 and to 90.7 and 96.3 %, in 2022, respectively. The acceptance rate for tCV% remained in the 90 % range for eight years. When creatinine <3 mg/dL, mean absBias%, and mean TE% improved significantly in 2021-2022 compared to 2015-2016 (p<0.05). When creatinine >3 mg/dL, acceptance performance did not improve. Mean tCV% remained consistent annually regardless of creatinine concentration. No significant variations in test methods were observed. CONCLUSIONS: The collaboration between academia and the government improved creatinine testing quality. Nevertheless, KR-STDZN must be expanded and refined.

Design optimization and implementation of a Fourier transform spectrometer with rotating motion for 0.1†cm-1 resolution spectroscopy.

In this paper, we present the design optimization and implementation of a high-resolution near-infrared Fourier transform spectrometer (FTS) based on a rotating motion. The FTS system incorporates a rotating mirror-pair for scanning the optical path length (OPL). The design optimization process is performed to maximize the scanning range to obtain a resolution of 0.1 cm-1 while taking into account constraints on the volume of the system and the availability of commercial optics. By using a pattern search algorithm, we optimized the geometrical parameters of the rotating part, and found the best solution to satisfy the constraints. A data processing method is implemented to correct the nonlinear OPL scanning using a He-Ne laser. The performance of the implemented FTS is verified through spectral analysis within the spectral range of 1550 ± 25 nm. This spectral band corresponds to the wavelength range of the amplified spontaneous emission (ASE) obtained from an Er-doped fiber amplifier used in this study. Additionally, gas spectroscopy conducted using the FTS system successfully detects and analyzes the distinct absorption lines of hydrogen cyanide in 16.5 cm gas cell. The detection sensitivity of a single measurement is evaluated based on the noise equivalent absorption coefficient of 1.45 × 10-5 cm-1 Hz-1/2 calculated from 5-sec measurement time, 2000 spectral elements, and 208 signal-to-noise ratio with 0.2 scan/sec.

The biasing effects of selection and attrition on estimating the mean.

Organizational and validation researchers often work with data that has been subjected to selection on the predictor and attrition on the criterion. These researchers often use the data observed under these conditions to estimate either the predictor or criterion's restricted population means. We show that the restricted means due to direct or indirect selection are a function of the population means plus the selection ratios. Thus, any difference between selected mean groups reflects the population difference plus the selection ratio difference. When there is also attrition on the criterion, the estimation of group differences becomes even more complicated. The effect of selection and attrition induces measurement bias when estimating the restricted population mean of either the predictor or criterion. A sample mean observed under selection and attrition does not estimate either the population mean or the restricted population mean. We propose several procedures under normality that yield unbiased estimates of the mean. The procedures focus on correcting the effects of selection and attrition. Each procedure was evaluated with a Monte Carlo simulation to ascertain its strengths and weaknesses. Given appropriate sample size and conditions, we show that these procedures yield unbiased estimators of the restricted and unrestricted population means for both predictor and criterion. We also show how our findings have implications for replicating selected group differences.

Strategies to shorten turnaround time in outpatient laboratory.

BACKGROUND: Turnaround time (TAT) is one of the most important indicators of laboratory quality. For the outpatient routine chemistry tests whose results are checked by clinicians on the same day, we set a quality goal that >90% of these samples should be reported within 60 min. As more than 20% of the samples failed to achieve this goal in 2020, we introduced an additional autoanalyzer and a real-time monitoring system to improve this rate. METHODS: As the TAT of the pre-analytical phase is the greatest contributor to TAT, we divided it into sampling, sample transport, and sample preparation times. An additional autoanalyzer was introduced, and its effect on TAT improvement was evaluated with the TAT data of June and July 2020. A real-time monitoring system was introduced to sort delayed samples, and its effect was assessed with the TAT data of June and July 2021. TAT data from December 2019 to January 2020 were set as baseline controls. RESULTS: The preparation time comprised the largest proportion of TAT. Although there was a slight decrease in overall TAT after the introduction of the above two strategies, the target TAT achievement rate increased significantly from 78.5% to 88.7% (p < 0.001). CONCLUSIONS: We checked the cause of TAT prolongation and introduced new strategies to improve it. The addition of an autoanalyzer per se was not so effective but was better when combined with the real-time monitoring system. Such strategies would increase the quality of the laboratory services.

The problem of measurement bias in comparing selected subgroups.

Estimates of subgroup differences are routinely used as part of a comprehensive validation system, and these estimates serve a critical role, including evaluating adverse impact. Unfortunately, under direct range restriction, a selected mean ( µÌ‚t' ) is a biased estimator of the population mean µx as well as the selected true score mean µt' . This is due partly to measurement bias. This bias, as we show, is a factor of the selection ratio, the reliability of the measure, and the variance of the distribution. This measurement bias renders a subgroup comparison questionable when the subgroups have different selection ratios. The selected subgroup comparison is further complicated by the fact that the subgroup variances will be unequal in most situations where the selection ratios are not equal. We address these problems and present a corrected estimate of the mean difference, as well as an estimate of Cohen's d* that estimates the true score difference between two selected populations, (µtA'-µtB')/σt . In addition, we show that the measurement bias is not present under indirect range restriction. Thus, the observed selected mean µÌ‚t' is an unbiased estimator of selected true score mean µty' . However, it is not an unbiased estimator of the population mean µy . These results have important implications for selection research, particularly when validating instruments.

First case report of Solobacterium moorei bacteremia due to acute cholangitis in South Korea.

Solobacterium moorei is an anaerobic gram-positive bacillus that rarely causes bacteremia. Herein, we report a case of S. moorei bacteremia associated with acute cholangitis in a patient without malignancy. The patient had a history of chronic pancreatitis with pancreaticogastrostomy and presented with fever and abdominal pain. Computed tomography scans showed acute cholangitis and S. moorei identified in blood cultures were confirmed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and 16S rRNA sequencing. The patient was successfully treated with endoscopic retrograde biliary drainage and antibiotics including meropenem and piperacillin-tazobactam.

The Prevalence of Metabolic Syndrome and Its Related Risk Complications among Koreans.

There is an increasing number of metabolic syndrome (MetS) patients worldwide, and there is no exception in South Korea. The risk complications of metabolic syndrome have been investigated by many previous research studies, while no data on any current trends of MetS are available. Therefore, the present study investigates the recent prevalence of MetS and its associated risk complications in Korean adults by using the Korean National Health and Nutrition Examination Survey (KNHANES). The Survey respondents (n = 4744) were adults over the age of 30, and they had participated in KNHANES 2016, which is a health survey of a national representative sample of non-institutionalized civilian South Koreans. The cross-tabulation analysis was applied to figure out the general characteristics impacting on the prevalence of MetS; furthermore, the odds ratios and 95% confidence intervals (CIs) using multivariate logistic regression analysis were presented for the risk complications of MetS. Findings from this study indicated that subjective health status, family structure, age, income level, use of nutrition labelling and gender showed significant connections with the prevalence of MetS. The risk diseases, stroke (OR = 2.174, 95% CI = 1.377-3.433, p < 0.01), myocardial infarction (MI) (OR = 2.667, 95% CI = 1.474-4.824, p < 0.01) and diabetes (OR = 6.533, 95% CI = 4.963, p < 0.001) were explored and verified attributable to the prevalence of MetS. The findings in this study suggest that sociodemographic characteristics-concentrated strategies are vital to prevent the prevalence of MetS in South Korea, and relative risk complications ought to be cautiously dealt with as well.

Usability of the Thera-Band® to improve foot drop in stroke survivors.

BACKGROUND: Stroke survivors show "foot drop", dragging their toes on the ground in the swing phase of gait. Ineffective ankle dorsiflexion may result in an abnormal gait pattern. OBJECTIVE: The purpose of this study was to investigate the effect of ankle Thera-Band® use on gait patterns in stroke survivors. METHODS: Gait data were collected in eight subjects who had had strokes using gait analysis system, both with and without the Thera-Band®. The following dependent variables of gait parameters were analyzed: velocity, cadence, step length, stride length, single support time, and double support time. RESULTS: There were significant improvements in gait velocity, cadence, stride length, and double support time in those who used the Thera-Band® compared to those who did not (p <  0.05). However, there were no significant differences in step length or single support time (p >  0.05). CONCLUSIONS: The results show that ankle Thera-Band® use may have a positive effect in improving gait parameters by increasing the ankle stability in stroke survivors with foot drop. Its usefulness in the rehabilitation of foot drop in stroke survivors needs to be further investigated.

A novel hinged ankle foot orthosis for gait performance in chronic hemiplegic stroke survivors: a feasibility study.

Stroke survivors with gait disturbances may use ankle foot orthoses (AFOs). However, most AFOs come in one-piece styles, which make it difficult for spasticity-affected stroke survivors to don. AFOs are also limited since they do not properly prevent ankle joint for foot drop by itself. Therefore, the present study developed a novel hinged AFO by adding a locking device to a hinged joint. We then tested its feasibility in 9 hemiplegic stroke survivors by investigating temporal-spatial gait parameters using the GAITRite in the following 3 conditions: no AFO, traditional AFO, and novel hinged AFO. There was no significant difference in spatiotemporal gait parameters among the different conditions. There were greater decreases in gait velocity, cadence, step length, and stride length in the novel hinged AFO group than in the no AFO and traditional AFO groups. This novel hinged AFO was developed to prevent foot drop. However, the AFO did not show significant differences in gait parameters because it consists of metal with extra weight and volume. Functionally, it prevented foot drop. It also improved convenience by its releasable design. Thus, further studies are needed to develop an AFO that improves gait and is convenient to use for hemiplegic stroke survivors.