Is the "rainbow test" for CSF within body fluid reliable?

On a call I tried this and didn't see the "rainbow" but turns out it be CSF after all...Is the "rainbow test" for CSF within body fluid reliable?
Actually, I be taught one and the same thing contained by school, but, as far as I can share, it remains anecdotal, with no unadulterated data allowing an intelligent answer to your query regarding reliability. I've see some patients with traumatic CSF leak in whom this be positive, but I've also seen CSF leak in which it wasn't. Like the anesthesiologist, above, I've used bedside glucose strips, but the beta-2-transferrin tryout is actually diagnostic.
I hold been giving spinal anesthesia and doing diagnostic spinal tap for 30 years and I never heard of such a entity.
When we do epidurals and clear fluid comes out of the needle, we trial the fluid with a glucose try-out strip to distinguish it from local anesthetic.