@lkirnbauer Doctors begin with your symptoms at the start of this journey and that leads to test options. Based on blood results the path can likely move into more blood draws and even to other tests, including imaging, which was the case for me. I've tried to capture some of the tests that people have posted in the 19 different groups in the Long Covid posts here on Mayo Clinic that eventually lead to reasons for the the lingering symptoms. It is a 'vast' landscape of tests. I spent 2 years in the mysterious unknown until the test for my 'T-Cells' was ordered. Below are some of the other reported tests from members in the Covid Long groups that lead to some answers and in some cases, real solutions. I've tried to capture some of the tests that people have posted in the 19 different groups in the Long Covid posts here on Mayo Clinic and it is a 'vast' landscape of experiences for patients. Please note, every body is unique and if you feel it's time to find a more 'investigative' doctor to help you on this journey, then do so.

These is a summary of tests I've captured from the Mayo Clinic posters for experiences they are having with testing for Long Covid:

1. SARS-CoV-2 Antibody Profile Test: CoV-2 Antibody Profile. Looking for Spike AB Dilution (normal range < 0.8 U/ml). (Note: some patients called this test D Timer. Test looks for micro-clotting and provides a 'numeric value' for bloods spike protein counts. Also, LabCorp can do this test.) This was often reported in the Mayo Clinic groups as a count from 17,000 to 25,000). The pathology of the spike protein is that it attaches to ACE 2 receptors and nicotinic receptors decreasing the ability to be released and metabolized. This causes overall inflammation throughout. Clotting cascade occurs leading to micro-clotting and hypoxic tissue causing cellular dysregulation. Anti-body response increases spike antibodies that also cause inflammation. Goal of therapy is to help release spike protein from cells, decrease overall inflammation and address micro-clotting with a layered treatment approach.
1a This may be same test as Item 1. above but it appeared to have a different name: Mast Cell Activation tests response to the spike protein, indicates the mast cells need to be under control before going after the spike proteins and micro clotting.
2. PAI-1 gene polymorphism which is a genotype test to see if body is having a hard time breaking down 'clots' in the blood vessels.
3. ANA Antibodies are proteins that your immune system makes to fight foreign substances, like viruses and bacteria. But an antinuclear antibody attacks your healthy cells instead. It's called "antinuclear" because it targets the nucleus of the cells, which is in charge of sending signals that are needed for important cell functions.
4. Amyloid Fibrin blood clot testing: to determine id blood clots are in the vessels as they constrict oxygen levels.
5. Levels for vitamins: D2, B's such as B12, B6, folates
6. Immunity blood work up and study for Tcells and T cytotoxic cells, ratios and absolutes including CD 3, CD 8, CD 4, CD 16, CD56
7. Comprehensive blood tests (CBC panels)