Background and objectives: The ABO antibody (Ab) titration tests are used in monitoring in ABO-incompatible (ABOi) solid organ transplantation (SOT). However, currently developed ABO Ab tests show Ab binding reactions. This study attempted to measure ABO Ab level using complement-dependent cytotoxicity (CDC). Materials and methods: We studied 93 blood group O serum samples from patients who underwent ABOi SOT from January 2019 to May 2021. Patients’ sera were incubated with A1 or B cells and added to a human complement solution. Supernatants were collected after centrifugation, and free hemoglobin (Hb) was measured by spectrophotometry. We converted plasma Hb value to hemolysis (%), which were compared with ABO Ab titer. Results: We found a mild correlation between hemolysis and ABO Ab titers. In simple regression analysis, the correlation coefficients were within 0.3660–0.4968 (p < 0.0001) before transplantation. In multiple linear regression analysis, anti-A hemolysis (%) was higher in immunoglobulin M (IgM) (β = 12.9) than in immunoglobulin G (IgG) (β = −3.4) (R2 = 0.5216). Anti-B hemolysis was higher in IgM (β = 8.7) than in IgG (β = 0.0) (R2 = 0.5114). There was a large variation in hemolysis within the same Ab titer. Conclusions: CDC can be used in a new trial for ABO Ab measurement. Furthermore, IgM rather than IgG seems to play a significant role in vivo activity, consistent with previous knowledge. Thus, this study may help in the development of the ABO Ab titration supplement test for post-transplant treatment policy establishment and pre-transplant desensitization.

Yousun Chung, Jin Seok Kim, Hee-Jeong Youk, Sang-Hyun Hwang, Heung-Bum Oh, Hyungsuk Kim, and Dae-Hyun Ko. Lab Med Qual Assur 2022;44:99-104. https://doi.org/10.15263/jlmqa.2022.44.2.99

Background/Aim: Bacterial and viral gastroenteritis present with overlapping symptoms, including vomiting, diarrhea, and abdominal pain. Stool tests have been used to differentiate between them; however, stool cultures are time-consuming and stool polymerase chain reaction (PCR) tests are expensive. The role of the clinical value of procalcitonin (PCT) and C-reactive protein (CRP) as diagnostic markers of bacterial gastroenteritis remains to be investigated. This study evaluated the diagnostic value of PCT for the early diagnosis of bacterial gastroenteritis. Methods: The medical records of patients diagnosed with gastroenteritis by the emergency department with positive stool PCR results confirming the diagnosis between 1 January 2020 and 31 July 2024 were retrospectively reviewed. Demographic characteristics and laboratory findings, including PCT and CRP levels, were analyzed. The area under the curve (AUC) for the diagnosis of bacterial gastroenteritis was assessed to determine the diagnostic potential of PCT and CRP. Results: Among the 1882 cases identified, 1435 met the inclusion criteria. CRP exhibited a sensitivity of 79.0% and specificity of 78.6% (AUC: 0.848, 95% CI: 0.815–0.881) in diagnosing bacterial gastroenteritis. In comparison, PCT showed lower sensitivity (60.3%) and specificity (62.6%) (AUC: 0.660, 95% CI: 0.614–0.706). However, in patients aged >17 years with fever (≥38 °C), PCT demonstrated an improved AUC of 0.767 (95% CI: 0.603–0.932; p = 0.019). Conclusions: CRP demonstrated moderate sensitivity in predicting bacterial gastroenteritis; however, its false-negative rate suggests limitations in clinical decision-making. While PCT may assist clinicians in identifying bacterial gastroenteritis in febrile adult patients, its diagnostic accuracy remains suboptimal, necessitating further validation through larger studies.

Hee-Jeong Youk, M.D., Yousun Chung, M.D., Hyungsuk Kim, M.D., Sang-Hyun Hwang, M.D., Heung-Bum Oh, M.D., Dae-Hyun Ko, M.D.. KJBT 2021;32:174-80. https://doi.org/10.17945/kjbt.2021.32.3.174