The disclosed invention pertains to methods for diagnosing clinical conditions that are common in hemodialysis patients and that may be related to abnormal carnitine metabolism resulting from hemodialysis. Further, the present invention pertains to methods for monitoring and improving the administration of therapeutic intravenous levocarnitine to such patients. Clinical algorithms have been developed for the clinical symptoms seen in end-stage renal disease (ESRD) patients that may be related to carnitine deficiency. Monitoring tools to assist healthcare professionals in implementing the clinical algorithms are also provided.