Your first test, the Do Health Annual Screen, is a broad 50+ marker panel covering metabolic, cardiovascular, kidney, liver, hormonal and thyroid health.
Your follow-up tests at month 4 and month 8 focus on the 11 Do Health Core markers. These are the markers most responsive to everyday lifestyle change and the ones that matter most for your long-term health, so they are the ones worth re-measuring every few months.
Your biological age is calculated from these core markers. That means each test can be compared directly to the last using your biological age alone, which is the clearest way to see whether your habits are moving the needle. The broader 50+ panel then runs again once a year.