Am actual doctor. I think we’re both closer to and further away from a Tricorder than you think.

Point of care ultrasound has been booming for the last 1-2 decades. There are now cell-phone sized wireless probes you can easily put in your pocket and do multiple diagnostic scans on the heart, lung, belly, etc with the caveat that you have to be adept at both obtaining and interpreting ultrasound images which certainly takes a lot of process.

There are devices about as big as 2-3 cell phones (think label maker or portable speaker sized) which can reliably run a whole panel of common blood tests including electrolytes, a blood gas, and hemoglobin on a 1-2mL blood sample in <5min. We also have dedicated point of care A1C devices, PT/INR devices, and probably some more I don’t know about.

I don’t think we’ll ever have handheld ultrasound/CT solely due to the significant radiation risk the operator would experience, even if the technology could be miniaturized.

I don’t think handheld MRI will ever happen either. The power requirement alone for the magnet strength needed is immense, not to mention the dangers of the magnetic field in some random unsecured area and the length of normal scans makes a handheld device impractical.

I don’t think we’ll ever have “bloodless” comprehensive blood testing. There’s only so much you can do with spectroscopy, and some things like electrolytes are in dramatically different concentrations between the cells and the blood so scanning through skin would likely dramatically alter readings.

TLDR we are actively miniaturizing some medical technologies. There are physics limitations in "handheld-izing " most non-ultrasound diagnostic imaging, and while we’ve certainly made great progress in point of care labs, I don’t think we’re going to get a device that can measure those things without a blood sample.