Reader tube

A reader tube was a multipurpose piece of mid-23rd century medical technology, specifically designed for field use, and typically issued with a standard medkit. It was also commonly used in sickbay surgeries as well. 

The reader tube, which was similar in function to a medical scanner, was used while placed near the patient's skin, and would display multicolored lights representing numerous body readings, including the heart rate, pulse rate, body temperature, and blood pressure. It was also capable of detecting the toxin level in a patient's body. The reader tube could also be used as a surgical device. 

In the alternate reality created by Nero's temporal incursion, Doctor used a reader tube to examine a Enterprise crew member in the aftermath of the destruction of Vulcan.

In 2268, Doctor Leonard McCoy used a reader tube during his emergency heart surgery on Ambassador Sarek. Later that year, Spock used a reader tube to removed Dr. McCoy's instrument of obedience. McCoy in turn would also use a reader tube to remove Natira's instrument of obedience. 

In 2269, Dr. McCoy used a reader tube to monitor Hikaru Sulu's progress after recovering from the poison of the retlaw plant on Phylos.