Do i have to get some blood tests before doing a lumbar mri without dye?

Not usually: Mri without contrast/dye does not require pretesting with labs.

No: Not unless you need anesthesia. Then you will need a full history and physical, and whatever pre-anesthetic testing your anesthesiologist sees fit to ensure your safety.

No: There is no need for blood tests before a non-contrast mri. However, if there is a chance that contrast might be used during the test, then it's easier to have a simple kidney function blood test before the MRI scan rather than having to get out of the scanner, have the test and then have to reschedule a scan with contrast.