Asking "what blood tests should I get?" is the right start, and the answer depends on your symptoms. A typical first set covers a complete blood count, a metabolic panel with glucose and kidney and liver tests, thyroid tests, and the inflammation markers ESR and CRP (CDC). These look for common, treatable causes. If they come back normal, broader immune testing can add data.
Key takeaways
- A standard first set looks for anemia, diabetes, kidney and liver problems, thyroid disease and broad inflammation (CDC).
- Your symptoms should choose the tests: a 2023 review found that testing without specific indications changes management in about 5% of patients (American Family Physician, 2023).
- Some conditions need specific tests: a stand or tilt test for POTS, a tryptase timed to a flare for mast cell activation (HRS; consensus criteria).
- Long COVID has no approved laboratory test, and routine results may be normal in people who have it (CDC).
- Broad immune panels measure what routine tests leave out. They add data and do not diagnose.
What blood tests should I get first?
A doctor chooses tests from your history and an examination. The CDC's list of basic screening tests for clinicians evaluating ME/CFS shows the usual first set for someone who feels unwell for a long time (CDC):
| Test | Checks | Looks for |
|---|---|---|
| Complete blood count with differential | Red cells, white cells and platelets | Anemia, infection, blood cell disorders |
| Metabolic panel | Glucose, electrolytes, kidney and liver function | Diabetes, electrolyte imbalance, kidney or liver disease |
| Thyroid tests (TSH, free T4) | Thyroid hormone signalling | An underactive or overactive thyroid |
| ESR and CRP | Broad, downstream inflammation | Infection or active inflammatory disease |
| Antinuclear antibodies, rheumatoid factor | Autoantibodies | Autoimmune conditions, when the history suggests one |
| Urinalysis | Urine chemistry and cells | Kidney and urinary tract problems |
Your doctor may add others, such as iron studies or vitamin B12, depending on your history. Bring a list of everything you take, including supplements, and copies of earlier results so your doctor can avoid repeating tests without reason.
Which blood tests fit which symptoms?
Symptoms narrow the list. The table matches common patterns to the tests guidelines describe.
| Pattern | Tests to discuss | Notes |
|---|---|---|
| Fatigue or malaise for weeks | Blood count, metabolic panel, thyroid tests, ESR, CRP | Looks for anemia, thyroid disease and other common causes (AFP) |
| Racing heart or dizziness on standing | Blood count, TSH, electrolytes, ECG, then an active stand or tilt table test | Clinicians diagnose POTS from the response to standing (CCJM; HRS) |
| Flushing, hives or gut flares | Baseline tryptase, plus a tryptase drawn within hours of a flare | The rise has to exceed 120% of baseline plus 2 ng/mL (consensus) |
| Symptoms since an infection months ago | Routine tests to look for other causes | No approved laboratory test for long COVID (CDC) |
| Widespread pain with poor sleep | Blood count and thyroid tests to rule out look-alikes | Clinicians diagnose fibromyalgia from clinical criteria (AFP) |
Each pattern has a guide of its own: fatigue and post-exertional malaise, the POTS test, the MCAS test, long COVID and the fibromyalgia blood test.
Are more blood tests better?
A long list of tests feels thorough, and it can mislead. A 2023 review for family doctors found that testing without specific indications changes management in about 5% of patients (American Family Physician, 2023). Each extra test adds a chance of a borderline result, which can lead to more tests and more cost without an answer. Our piece on the cost of tests that show nothing covers that trap.
Some markers answer questions other than the one you are asking. Cardiology, for example, has studied the hs-CRP test as a cardiovascular risk marker (review, 2009), so a result sits in a context your doctor needs to explain.
What if your blood tests come back normal?
A normal first set makes the common causes less likely, and that matters. It says little about the immune signalling a standard panel does not measure: CRP, the one inflammation marker it includes, reads inflammation downstream of IL-6 (Hunter and Jones, 2015).
From there, three steps help. Ask which conditions remain open, and which of them need a specific test. Keep a dated symptom record. Consider measurement over time: a marker measured at intervals to assess change is what the FDA-NIH BEST glossary calls a monitoring biomarker (BEST). Broad immune panels read cytokines such as IL-6 and TNF-α, interferons and chemokines against a healthy reference, and in research, profiling many measures separated long COVID from recovery at the group level (Klein et al., 2023). They do not diagnose.
Where Mune Mirror™* fits
Mune Mirror™ measures more than 1,000 immune and inflammation proteins from an at-home sample, benchmarks each against a healthy reference and repeats the measurement over time. It comes after the standard first set and adds to it. Unwellness testing is blood testing for people whose standard labs come back normal but who still feel unwell: the people medicine has no answers for yet. It measures highly selected immune and inflammatory proteins that routine panels do not, so persistent symptoms can be tracked and made visible against a healthy reference. Mune Mirror™ is investigational and for research and informational use. It does not diagnose, treat, cure or prevent any disease.
You can see what Mune Mirror™ measures, and the guide to inflammation markers explains how it compares with CRP and ESR. You bring the results to your own doctor.
Frequently asked questions
What is a full blood panel?
People use the phrase for a first set of tests: a complete blood count and a metabolic panel with glucose, electrolytes and kidney and liver tests. Doctors add thyroid tests and inflammation markers such as ESR and CRP when symptoms point that way.
Should I ask for an inflammation test?
CRP and ESR are common first inflammation tests, and a doctor adds them when symptoms suggest inflammation or infection. They read inflammation downstream and leave most immune signalling unmeasured. Broader cytokine panels exist in research and specialist settings.
Can blood tests show long COVID?
No approved laboratory test can determine whether symptoms are due to long COVID, and routine blood tests may be normal in people who have it, according to the CDC. Doctors use blood tests to look for other causes and diagnose long COVID from the history and an examination.
Do I need to fast before blood tests?
Some tests, such as a fasting glucose, need an empty stomach. The laboratory or your doctor tells you when you book.
How often should blood tests be repeated?
Your doctor decides, based on the result and your symptoms. A marker measured at intervals to assess change is what researchers call a monitoring biomarker, and a series of results shows direction better than one.
Sources
- CDC. Evaluation of ME/CFS (for clinicians).
- Latimer KM, Gunther A, Kopec M. Fatigue in Adults: Evaluation and Management. American Family Physician, 2023.
- Fibromyalgia: Diagnosis and Management. American Family Physician, 2023.
- Evaluating and managing postural tachycardia syndrome. Cleveland Clinic Journal of Medicine, 2019.
- Sheldon RS, et al. 2015 Heart Rhythm Society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm, 2015.
- Selecting the right criteria and proper classification to diagnose mast cell activation syndromes: a critical review. Journal of Allergy and Clinical Immunology: In Practice, 2021.
- CDC. Long COVID Basics.
- The use of high sensitivity C-reactive protein in clinical practice. Review, 2009.
- Hunter CA, Jones SA. IL-6 as a keystone cytokine in health and disease. Nature Immunology, 2015.
- FDA-NIH Biomarker Working Group. BEST Resource: Monitoring Biomarker.
- Klein J, et al. Distinguishing features of long COVID identified through immune profiling. Nature, 2023.
Mune Mirror™ is currently in development, and the performance characteristics of this test have not yet been established. It is investigational. It does not diagnose, detect, screen for, treat, cure or prevent any disease. Results are for research and informational purposes, to discuss with your own doctor.