S-transthyretin analysis
S-transthyretin is a blood test that measures the level of transthyretin in serum. Transthyretin is a protein that is formed in the liver and functions as a transport protein for the thyroid hormone thyroxine (T4) and vitamin A via retinol-binding protein. Unlike many other liver proteins, transthyretin has a short half-life, which means that the level can change relatively quickly when there are changes in the body's protein synthesis.
Analysis to assess nutritional and liver status
S-transthyretin is analyzed primarily to assess nutritional status and liver protein synthesis. Since transthyretin responds quickly to changes, the analysis is often used when malnutrition, catabolic conditions or when following up on nutritional treatment are suspected.
When is transthyretin analysis recommended?
S-transthyretin is useful when you want to follow short-term changes in protein synthesis, for example in long-term illness, inflammatory conditions or when insufficient nutritional intake is suspected. The analysis can also be used as a complement to the assessment of liver function together with other common liver tests.
Interpretation of test results
Low levels of S-transthyretin can be seen in malnutrition, acute or chronic inflammation, liver disease or increased breakdown of the body's proteins. Since S-transthyretin is an acute-phase negative protein, the concentration can decrease in inflammatory conditions, which is important to take into account when interpreting the result. Elevated levels of S-transthyretin are uncommon and usually have limited clinical significance. A higher value is usually considered a normal finding and rarely requires further investigation.
S-transthyretin is almost always used as part of a comprehensive assessment and is usually interpreted together with other tests, such as albumin, CRP and liver status, as well as clinical symptoms and nutritional intake.
S-transthyretin may be relevant for you if you:
- Want to get a picture of the body's current protein synthesis.
- Suspect or follow up on malnutrition.
- Have long-term illness or inflammatory conditions.
- Want to supplement other liver and nutrition-related tests.
By measuring S-transthyretin, you get a more rapidly changing marker of nutritional status and liver protein synthesis compared to traditional liver proteins.
