an auc04 4500 microghrl 7 vs 40 p0041 or a c2 level1500 microgl 0 vs 58 p0001 on day 7 sensitivity 100 specificity 75 positive predictive value 58 negative predictive value 100 there was no evident relationship between csa exposure and renal toxicity within this patient sampleconclusions absorption of csa is highly heterogeneous immediately posttransplant although the pharmacokinetic profile normalizes interpatient variability decreases and csa absorption increases throughout the first 2 weeks permitting a reduction in neoral dose to achieve constant exposure trough c0 levels do not accurately predict csa exposure or rejection risk and should be replaced by sparse or single point c2 sampling methods which offer a high predictive value to optimize the use of this drug and reduce rejection risk acute rejection is significantly more common with low csa exposure during the first week posttransplant and levels above the threshold of approximately auc04 4500 microghrl or c2 1500 microgl are desirable to minimize the risk of rejection