(Patient Name) has a rare metabolic disorder called Cystinosis (ICD-9: 270.0). There are an estimated 500 individuals in the United States with this disease. Patients with this disorder accumulate large amounts of the amino acid cystine within their cells. By about one year of age, these children begin to have renal tubular problems leading to very high urine volume and loss of important substances in their urine. Without diagnosis, these patients may die at that time. With appropriate symptomatic treatment, they do relatively well for many years, but grow very poorly and are in end-stage renal failure at an average age of nine years. In the past, cystinosis patients then required dialysis or renal transplant to maintain life. As patients with cystinosis lived longer lives because of renal transplantation, many developed severe damage to other organs including the brain, retina, and muscles.

In 1994 the FDA approved cysteamine bitartrate (Cystagon™) as the only specific treatment for this disease. Unfortunately this drug is foul tasting and must be taken every 6 hours around the clock to be effective. Thus, it is essential that these childrens’ white blood cell cystine be monitored periodically. The FDA approved package insert asks that the test be performed every three months. The reason that this measurement is done so frequently is that this is the only way to be certain that the patient has been prescribed the correct dose and that he/she is actually taking this dose. By frequently measuring the WBC cystine, we know when a patient stops being compliant and can immediately alert his/her physician. In patients who continue to be compliant we sometimes decide to do the measurement less frequently.

The other disease in which cystine is measured is cystinuria. This is a completely unrelated disorder in which the urinary cystine concentration is elevated. Many laboratories measure urinary cystine concentration. This is a relatively easy assay. The measurement of intracellular cystine is much more difficult and we are one of the few laboratories in the world who do this assay. The University audits the laboratory and insists that we charge an amount for this assay that will exactly cover our expenses. In other words, we can neither make nor lose money. Although we have "applied" to the AMA for a specific CPT code for this test, this is still on hold so we are forced to use the codes 83789 and 84999. We have been told that it is unlikely that they will ever give a CPT code for use in such a rare condition.

Unless another form of treatment becomes available, cystinosis patients will remain on this treatment for the rest of their lives. Cystinosis patients who are able to faithfully take cysteamine as prescribed greatly delay their need for kidney transplantation while increasing their ability to live relatively normal lives. This drug also prevents damage to other organs.

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