Potassium citrate mixture

Citrate, a tricarboxylic acid cycle intermediate, plays a central role in renal physiology by acting as both a urinary base equivalent and a potent inhibitor of calcium stone formation. Hypocitraturia, a common metabolic abnormality in calcium nephrolithiasis, is not a binary disorder but a continuum shaped by acid-base status, diet, potassium balance, proximal tubular handling, and systemic citrate status. We provide an update on the biology of citrate, renal regulation of its excretion, clinical pathophysiology, and treatment of hypocitraturia. Identical urinary citrate levels may have different implications depending on systemic acid-base status and urinary calcium excretion. Hypocitraturia prevalence is increasing, paralleling rises in metabolic syndrome, obesity, and dietary habit changes. Experimental models confirm that systemic or intracellular acidosis, potassium deficiency, and upregulation of renal transport and metabolism of citrate reduce urinary citrate, enhancing stone risk. Potassium citrate remains the cornerstone of therapy, increasing both urinary citrate and pH. However, its use requires caution in calcium phosphate stone formers and patients with chronic kidney disease. Citrate resistance, defined as inadequate urinary citrate response despite good potassium delivery, is a therapeutic challenge. Novel interventions including sodium-dicarboxylate cotransporter-1 (NaDC-1) inhibitors and citrate analogs such as hydroxycitrate may offer future alternatives. In conclusion, urinary citrate must be interpreted within physiological and clinical contexts. Recognizing hypocitraturia as a modifiable, non-binary risk factor allows for more precise risk stratification and individualized therapy in stone prevention, particularly when lithogenicity overlaps with acid-base and renal abnormalities.

Abstract licence: CC BY

BACKGROUND: As the processed blood volume increases, a larger amount of anticoagulant (AC) is required, which leads to a serious issue of fluid dilution in large-volume leukocytapheresis (defined as ≥3-fold total blood volume). We previously reported a novel method for allogeneic peripheral blood stem cell harvest (PBSCH) using highly concentrated sodium citrate (HSC; 5.32%), which shortened the procedure time and reduced the need for an AC solution without heparin. In this study, we extended this novel method to autologous PBSCH (auto-PBSCH) and compared it with patients who received auto-PBSCH using normal concentrated sodium citrate (NSC; 2.2%). STUDY DESIGN AND METHODS: We retrospectively analyzed consecutive auto-PBSCH data obtained using the Spectra Optia continuous mononuclear cell collection mode between May 2017 and May 2025 at our institution. RESULTS: Leukocytapheresis was performed using NSC in 36 patients and HSC in 22. In the HSC group, patients tended to be younger, had significantly lower body weight, and had significantly fewer hematopoietic tumors as primary diseases compared to the NSC group. After propensity score-matched cohort adjusted for patient background, the total amount of AC solution was significantly lower (694 [range, 77-1648] vs. 298 mL [range, 64-797], p = .02), and procedure time was significantly shorter (224 [range, 117-395] vs. 181 min [range, 103-309], p = .048) in the HSC group. Furthermore, the loss rates of magnesium and potassium were lower in the HSC group. CONCLUSION: This novel leukocytapheresis method demonstrated the efficacy and safety in auto-PBSCH, while minimizing the patient burden.

Abstract licence: CC BY-NC