Blood Tests by Condition
Last updated: September 14, 2026
Doctors rarely diagnose a condition from one blood test alone. Each guide below explains which labs are typically ordered to check for a specific condition, what each test measures, and how the results are read together.
How Condition-Based Testing Works
When a healthcare provider suspects a condition such as anemia or a thyroid problem, they order a small group of tests whose results are most meaningful in combination. One abnormal value may be a temporary fluctuation; a consistent pattern across several related tests is far more informative.
These guides are educational. They explain what the tests measure and what abnormal patterns may suggest — they cannot interpret an individual result. A healthcare provider considers results alongside symptoms, history, and medications.
Guides by Condition
Anemia Blood Tests
CBC, hemoglobin, hematocrit, ferritin, and iron studies — how doctors check for anemia and tell iron deficiency apart from other causes.
Diabetes Blood Tests
Fasting glucose, A1C, and related tests — how prediabetes and diabetes are detected and monitored over time.
Thyroid Blood Tests
TSH, Free T4, and Free T3 — how an underactive or overactive thyroid shows up in blood work.
Kidney Blood Tests
Creatinine, BUN, and eGFR — the tests that show how well the kidneys are filtering the blood.
Liver Blood Tests
ALT, AST, and other liver enzymes — what elevated results may indicate and which patterns matter.
Inflammation Blood Tests
CRP and ESR — the markers doctors use to detect and track inflammation in the body.
Keep Exploring
- Lab Panels Explained — what the CBC, CMP, Lipid, and Thyroid panels measure.
- How to Read Your Lab Results — reference ranges, flags, and units in plain English.
- Test Comparisons — side-by-side explainers such as BUN vs creatinine and CRP vs ESR.