Fatty acids are fundamental as energy and structural source to the human cells. They are not usually found free in human circulation. Alteration in fatty acids metabolism is linked to diseases such as diabetes, preeclampsia, heart disease, and some infectious diseases. Increased levels of non-esterified fatty acids (NEFA) may cause cell dysfunction and lipotoxicity. Since physiologically fatty acids are transported bound to albumin, we propose here a simple and cheap test that consists of albumin isoelectric focusing determination to measure the potential systemic NEFA cytotoxicity. For validation of this method, albumin isoelectric focusing in 51 serum samples from 40 critically ill patients and 11 controls was compared with NEFA/albumin ratios measured by HPLC. We called this approach an albumin saturation test. This test may indicate to physicians the potential NEFA lipotoxicity guiding them throughout better patient management. The albumin saturation test can point out serum albumin-NEFA saturation through a cheap assay that could be performed by any care facility.