Cystine concentration in cerebrospinal fluid (CSF)

Why is this test done?

Your healthcare provider may order this test if you have symptoms like headaches, nausea, or neurological issues that could be linked to an amino acid disorder. It’s also used to check for conditions like cystinosis, a rare genetic disease that causes cystine buildup in organs.

What does the test involve?

A small amount of spinal fluid is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then sent to a lab for analysis. The test measures cystine levels in this fluid using a specialized method to detect its concentration accurately.

What should you expect before the test?

You may be asked to fast for a few hours before the test, though this isn’t always required. Wear comfortable clothing with loose sleeves or shorts, and bring any medications you’re currently taking. Inform your provider about any allergies or conditions that could affect the procedure.

What happens during the test?

The procedure involves lying on your side with your knees bent. A needle is gently inserted into your lower back to collect the spinal fluid. You may feel a slight pinch, but the process is usually quick and well-tolerated. You’ll be given instructions to avoid straining or moving too much afterward.