A CK-MB test may be used as a follow-up test to an elevated CK in order to determine whether the increase is due to heart damage or skeletal muscle damage.
Scuba organizations say recreational divers shouldn't go below about 130 feet, but one Egyptian diver recently ventured a bit deeper -- going more than 1,000 feet below the ocean surface and setting a world record in the process.
For example, if the planned dive depth is 60 feet, the diver should calculate the no-decompression limit for a dive to 60 feet and calculate a contingency no-decompression limit for a dive to 70 feet. If he accidentally exceeds the planned maximum depth, he simply follows his contingency no-decompression limit.