Modifier 25 should be appended to the office or other. outpatient service code to indicate that a significant, separately. identifiable E/M service was provided by the same physician. on the same day as the preventive medicine service.
The level of homocysteine in the blood can be measured with a simple blood test that is often, but not always, done after fasting. Homocysteine levels of 12 mmol/L are considered normal and levels below 10 mmol/L are considered desirable.
A homocysteine blood test is done to: 1  Help identify vitamin B12 deficiency or folic acid deficiency. But other tests for these deficiencies are available. 2  Help identify a rare inherited disease (homocystinuria) that causes a deficiency of one of several enzymes needed to convert food to energy.