University of California, San Diego
Biochemical Genetics / Cystine Determination Laboratory

SHIPPING ADDRESS (use this address to send samples):
UCSD Med Ctr- Biochemical Genetics
CTF - Bldg B Room 213
212 Dickinson St.
San Diego, CA 92103

Phone: +1- 619- 543-5260
Fax: +1- 619- 543-3565
email: cystine@ucsd.edu
http://biochemgen.ucsd.edu/cystinosis or http://cystinosiscentral.org

The intracellular cystine content of acid-stabilized white blood cells may be used to evaluate the cystine-depleting effect of CystagonTM or to diagnose (or rule out) new cystinosis patients. White cells are used because cystine is not elevated in red cells or plasma of cystinosis patients. (It is elevated in urine also, but this is not diagnostic.) The normal value is generally less than 0.2 nmol half cystine/mg white cell protein. The cystinosis value is generally greater than 2 nmol half cystine/mg white cell protein.

Reminder: Blood must be taken 5-6 hours after a dose of CystagonTM and processed immediately for the white cell cystine measurements to be meaningful.

To be used for diagnosis and to monitor cystinotic patients taking CystagonTM

Please refer here for Note to Laboratory Personnel responsible for leukocyte preparation.
First time requests: Show procedure to laboratory personnel. It will take about an hour and a half of their time. For first time preparers, we would like to have a normal control.
Diagnostic samples: A normal control sample is required (no charge); control need not be ethnic-, gender-, or age-matched, but must not be a relative. Control must be prepared alongside patient sample.
Please refer to the printed protocol posted here (PDF)
Step-by-step illustrated protocol posted here