Green Cross Laboratories

As astroviral infection rapidly increased in the summer of 2022 in Korea, this study aimed to determine the cause and genotype of astroviruses during this period. From January to December 2022, we tested 43,312 stool samples from patients with acute gastroenteritis utilizing multiplex PCR to detect HAstV. For the HAstV-positive samples, we determined the genotypes of the HAstVs by PCR and sequencing. The monthly positive rate from 2015 to 2022 showed a notable and abrupt increase of HAstV infection between June and August 2022, peaking at 9.8% in July 2022. The annual positivity rate of HAstV remained at 2–3% between 2015 and 2019, and then decreased to 0.5% in 2020, followed by an increase to 1.5% in 2021 and 3.6% in 2022.The genotyped astroviruses in 2022 were all identified as HAstV-1 type, and the nucleotide identity% among them was >99%. The GenBank accession number for the strain genetically closest to the strains identified in our study was ON571597.1, which was HAstV-1 isolated from Pingtan in 2019. Our results provide recent epidemiological data on HAstVs in Korea. The decline and surge in astrovirus positivity in recent years may be related to the COVID-19 pandemic.

Effect of blood collection tubes on vitamin D immunoassay results.We examined the effect of blood collection tubes on 25-hydroxyvitamin D (25(OH)D) as part of an end-user verification, with approval from the institutional review board (IRB) of Seoul St. Marys Hospital (IRB Number KC23DSSF0058).The following four tubes were examined for potential assay interference: Greiner Bio-One Vacuette 8-mL serum-separator tube (SST) (Greiner Vacuette; Cat. #455071KR, lot #A2309376; Greiner Bio-One, Kremsmunster, Austria), Becton Dickinson (BD) Vacutainer 8.5-mL SST (BD Vacutainer; Cat. #367528, lot #2237485; BD, Franklin Lakes, NJ, USA), AB Medical V-Tube 8-mL tube with clot activator and gel (V-tube; Cat. #301802, lot #8337002; AB Medical, Seoul, Korea), and AB Medical VQ-Tube 8-mL with clot activator with thrombin and gel (VQ-tube; Cat. #B0180B, lot #8B41002; AB Medical).Serum samples from our apparently healthy volunteers (two men and two women; age range, 26-49 yrs) were collected in each of the abovementioned tubes and analyzed for 25(OH)D using the Atellica IM Vitamin D Total assay.Our apparently healthy volunteers (two men and two women; age range, 26-49 yrs) were collected in each of the abovementioned tubes and analyzed for 25(OH)D using the Atellica IM Vitamin D Total assay.Addnl., serum samples of three other apparently healthy individuals were collected in both Greiner Vacuette and VQ tubes for anal.Samples collected in Greiner Vacuette tubes exhibited higher 25(OH)D values (mean bias, 6.22 ng/mL) than those collected in VQ tubes when analyzed with the Siemens Atellica IM system.Our study is limited by its small sample size.Nevertheless, examining various tubes with specimens obtained from healthy individuals is not readily accessible in routine practice, and our findings clearly show the impact of additives in blood collection tubes on vitamin D immunoassay results.

Vitamin D (vit-D) deficiency is highly prevalent in the Korean population, highlighting the need for accurate measurements. In this study, the interferences by endogenous and cross-reactive substances were compared between routine vit-D immunoassays and mass spectrometry (MS) methods.

Two MS methods and 4 immunoassays from different manufacturers (Abbott, Beckman Coulter, Roche, Siemens) were compared. Residual samples that were icteric, lipemic, hemolyzed, high in rheumatoid factor, from myeloma patients, or patients undergoing hemodialysis were collected. Also, 4 levels of National Institute of Standards and Technology (NIST) Standard Reference Material 972a, and 12 samples serially spiked with 3-epi-25-OH-D₃ were prepared.

Significant interferences were observed in hemolytic (Roche), icteric (Beckman and Siemens) and lipemic samples (all 4 immunoassays). Level 4 NIST material and 3-epi-25-OH-D₃-spiked samples induced significant cross-reactivity, yielding higher total vit-D measurements in non-epimer-separating MS methods, and both the Beckman and Roche immunoassays.

Most observed interferences were consistent with manufacturers' claims, but overall improvement of immunoassay bias limits is required. Awareness of potential interference is important to increase the accuracy of vit-D measurements. Moreover, care is due when interpreting vit-D results of newborns, infants and less commonly, pregnant women, who are known to have physiologically high levels of the highly cross-reactive 3-epi-25-OH-D₃.