It sounds like you are saying that the only thing on the W-2 is the value of the health insurance in Box 1 paid for you as a partner. In that case, this amount would be Box 1 only. The health insurance is not subject to social security and medicare.
If anything reported on the W-2 was subject to Social Security tax it would be in Box 3 and the SS withheld would be in Box 4. Likewise for Medicare, in Boxes 5 and 6 respectively.
Please comment if this is not what you are asking.
