A citrate content of 4% is recommended by the US regulatory authorities and others. In the context of one case of fatality, the FDA issued an advisory not to use a product with a higher citrate content (Tricitrasol, 46.7 %). Lock solutions of this type had to be recalled from the US market. Their use is no longer approved. Likewise, over-instillation of less than 1 mL per lumen of a 30% citrate solution induced transient cardiac arrest in two cases in the Netherlands (Punt CD, Boer WE, Cardiac arrest following injection of concentrated trisodium citrate, Clinical Nephrology 2008, 69 (4), 317-318). A high citrate content (46.7%) can also lead to embolic events which might be triggered by protein precipitation (Davenport A , Willicombe MK, Vernon K, Embolic complications from central venous hemodialysis catheters used with hypertonic citrate solution, American Journal of Kidney Diseases, 2010, 55, 348-351 / Schilcher G, Scharnagl H, Horina JH, Ribitsch W, Rosenkranz AR, Stojakovic T and Polaschegg H-D, Trisodium citrate induced protein precipitation in haemodialysis catheters might cause pulmonary embolism, Nephrol Dial Transplant (2012) 0: 1–5).