A 48-year-old man on ICU is receiving CRRT with citrate anticoagulation. His total calcium is 3.2 mmol/L but ionised calcium is only 1.05 mmol/L. The total:ionised ratio is greater than 2.5. What does this indicate?ANormal calcium homeostasisBCitrate accumulation - citrate chelates calcium, reducing ionised calcium while citrate-calcium complexes elevate total calcium; a ratio greater than 2.5 indicates citrate toxicity, typically from impaired hepatic citrate metabolism; reduce the citrate infusion rateCVitamin D excessDHyperparathyroidismELaboratory artefactCheck my answer