Boer W, van Tornout M, Solmi F, et al. - Researchers undertook this single-center retrospective observational analysis to determine potential determinants of the Total/ionized calcium ratio (T/iCa), a marker of citrate accumulation. They assessed citrate dose, citrate target, albumin, phosphate, pH, lactate, and APACHE II score as potential determinants. They constructed linear mixed models (LMM) using citrate dose and citrate target, reporting links with T/iCa. An LMM in 379 complete samples (95 patients) sets, from a dataset of 471 samples in 103 patients, showed that citrate dose, pH, phosphate, albumin and APACHE were interactively associated with T/iCa. An increasing citrate dose was shown to be related to a higher rise in T/iCa when phosphate was high, and less when phosphate was low. An increasing albumin was identified to be related to a higher rise in T/iCa when APACHE was high and phosphate was low and less when APACHE was low and phosphate high. In this study, apart from citrate dose, a high pH and high phosphate, albumin and APACHE were also found to be related to an increasing T/iCa.