Long COVID Blood Tests — What to Ask Your GP
There's no single blood test for long COVID. But there is a panel of tests that rules out other causes — and most are bulk-billed under Medicare.
The Short Answer
There is no blood test that diagnoses long COVID. Diagnosis is clinical — based on persistent symptoms (fatigue, brain fog, breathlessness, post-exertional malaise) lasting more than 12 weeks after a confirmed or probable COVID-19 infection, without another explanation.
What blood tests do is rule out other treatable causes of those symptoms: iron deficiency, thyroid disease, B12 deficiency, diabetes, autoimmune conditions, and vitamin D deficiency.
What Counts as Long COVID?
The World Health Organization defines post COVID-19 condition (the formal name for long COVID) as:
“The continuation or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation.”
Common symptoms include:
Persistent fatigue (most common)
Brain fog / poor concentration
Post-exertional malaise (crashing after activity)
Breathlessness / reduced exercise capacity
Heart palpitations / POTS
Sleep disturbance
Muscle and joint pain
Loss of smell or taste (persistent)
Headaches
Anxiety, depression, mood changes
Chest pain
Gastrointestinal symptoms
Most Australian GPs will start blood test investigations once symptoms persist beyond 4–12 weeks post-infection.
The Core RACGP Panel
These are the baseline tests the RACGP recommends for any patient with persistent post-COVID symptoms. All are bulk-billed when ordered by a GP.
Full Blood Count (FBC)
Purpose: Rule out anaemia, infection, blood disorder
Long COVID fatigue can mimic iron deficiency anaemia. The FBC also picks up subtle markers of chronic inflammation (raised neutrophils, low lymphocytes).
Urea, Electrolytes & Creatinine (U&E)
Purpose: Kidney function, sodium, potassium
Some long COVID patients develop kidney involvement, dehydration from POTS, or electrolyte issues. Baseline kidney function is also needed before some treatments.
Liver Function Tests (LFT)
Purpose: Rule out liver involvement
COVID-19 can cause persistent liver enzyme elevation in a subset of patients. Also screens for fatty liver, hepatitis, and side effects of medications.
C-Reactive Protein (CRP)
Purpose: Inflammation marker
Persistently elevated CRP suggests ongoing inflammation that may need investigation. A normal CRP doesn't rule out long COVID but helps narrow the differential.
Ferritin
Purpose: Iron stores + inflammation
Low ferritin = iron deficiency (a common cause of fatigue and brain fog in its own right). Very high ferritin suggests significant inflammation.
Iron Studies
Purpose: Detailed iron picture
Goes beyond ferritin: serum iron, transferrin, transferrin saturation, total iron binding capacity. Distinguishes iron deficiency from anaemia of chronic inflammation.
Vitamin B12 and Folate
Purpose: Deficiency that mimics fatigue and brain fog
B12 deficiency is one of the most under-diagnosed causes of persistent fatigue, neuropathy, and cognitive symptoms in adults. Treatable with supplements or injections.
TSH (Thyroid Stimulating Hormone)
Purpose: Rule out thyroid disease
An underactive thyroid (hypothyroidism) causes fatigue, brain fog, weight gain, and cold intolerance — symptoms that overlap heavily with long COVID. COVID-19 has also been linked to thyroiditis.
Vitamin D
Purpose: Deficiency contributing to fatigue/mood
Vitamin D deficiency is extremely common in Australia (especially in winter and for indoor workers) and contributes to fatigue, low mood, and muscle weakness. Easy to correct.
Fasting Glucose / HbA1c
Purpose: Diabetes screening
COVID-19 has been linked to new-onset diabetes. Diabetes itself causes fatigue, blurred vision, and poor wound healing.
Creatine Kinase (CK)
Purpose: Muscle damage marker
Useful if you have persistent muscle pain or weakness. Elevated CK suggests an underlying muscle process (myositis, statin-induced myopathy, severe deconditioning).
Additional Tests — Guided by Symptoms
Beyond the core panel, your GP may order extra tests depending on your specific symptoms. Don't expect all of these — they're ordered selectively.
BNP / NT-proBNP
Purpose: Heart failure marker (if breathless)
If you're breathless on minimal exertion, your GP may check this to rule out a cardiac cause. Long COVID can cause myocarditis or worsen pre-existing cardiac issues.
D-Dimer
Purpose: Blood clot screening (if breathless or chest pain)
COVID-19 increases clot risk. If you have unexplained breathlessness or chest pain, a normal D-dimer makes pulmonary embolism unlikely. A raised D-dimer needs further imaging.
Troponin
Purpose: Cardiac muscle damage (if chest pain)
If chest pain is significant, troponin can detect ongoing or recent heart muscle damage. Often done in emergency departments rather than GP rooms.
Antinuclear Antibodies (ANA)
Purpose: Autoimmune disease screen
If you have joint pain, rashes, dry eyes/mouth, or hair loss, ANA helps screen for autoimmune conditions that can be triggered or unmasked by COVID-19 infection.
Rheumatoid Factor and Anti-CCP
Purpose: Inflammatory arthritis (if joint symptoms)
Some long COVID patients develop a reactive or seropositive inflammatory arthritis. These tests help distinguish from osteoarthritis or fibromyalgia.
EBV / CMV Serology
Purpose: Reactivated viral infection
If you have persistent fatigue, swollen lymph nodes, or sore throat, testing for reactivated Epstein-Barr or cytomegalovirus may be considered. Evidence is still evolving.
Cortisol (Morning + ACTH if low)
Purpose: Adrenal insufficiency screen
Severe persistent fatigue, low blood pressure, and salt cravings can suggest adrenal insufficiency. Rare but treatable. Morning cortisol is a screening test.
Cortisol (24-hour Urine or Saliva)
Purpose: Adrenal stress assessment
Used by some integrative practitioners but evidence base is weaker than blood cortisol. Generally not Medicare-rebated.
Coeliac Screen (Tissue Transglutaminase IgA)
Purpose: Coeliac disease screen if GI symptoms
Coeliac disease is a common cause of unexplained fatigue and brain fog. If you have any gut symptoms, bloating, or weight changes, worth screening.
Mast Cell Activation Markers (Tryptase)
Purpose: MCAS screening
Mast cell activation syndrome is increasingly recognised in long COVID. Blood tryptase is a screening test; specialised testing requires a clinical immunologist.
POTS — A Common Long COVID Feature
Postural Orthostatic Tachycardia Syndrome (POTS) is one of the most common features of long COVID. It causes a rapid heart rate, dizziness, and light-headedness on standing — sometimes severe enough to cause near-fainting.
The simplest test is the NASA Lean Test (also called the active stand test). You can do a basic version at home before seeing your GP:
Lie down quietly for 5–10 minutes
Make sure you're relaxed and breathing normally. Take a baseline heart rate at the end.
Stand up against a wall
Don't move your legs once standing. Lean against a wall for safety. Have someone with you if you're prone to fainting.
Measure heart rate at 1, 3, 5, and 10 minutes
Use a fingertip pulse oximeter, smartwatch, or simply count your pulse for 60 seconds.
Compare standing heart rate to lying baseline
A sustained increase of >30 bpm (or >40 in adolescents) without a significant drop in blood pressure suggests POTS.
Sit down if you feel faint
Don't push through faintness. The test can be repeated on another day.
Long COVID Clinics in Australia
Most Australian states have at least one specialised long COVID clinic, usually in major teaching hospitals. They offer multidisciplinary care — respiratory physician, cardiologist, neurologist, rehabilitation medicine, psychiatry/psychology — in one place.
NSW
St Vincent’s Long COVID Clinic, Royal Prince Alfred (RPA), Westmead Hospital. GP referral required.
Victoria
Royal Melbourne Hospital Long COVID Clinic, Alfred Health, Austin Health. Long waits common.
Queensland
Princess Alexandra Hospital, Royal Brisbane and Women’s Hospital. Statewide telehealth available.
WA
Fiona Stanley Hospital and Sir Charles Gairdner Hospital have post-COVID services.
SA
Royal Adelaide Hospital and Flinders Medical Centre offer multidisciplinary care.
ACT / TAS / NT
Smaller services. Often access via telehealth to the larger east coast clinics through GP referral.
When Private Testing Is Worth It (and When It Isn't)
Worth paying for
- A private GP consultation with a doctor experienced in long COVID or chronic fatigue. A good 45-minute appointment is worth more than $300 of fancy blood tests.
- Saliva or 24-hour urinary cortisol if there's a strong clinical suspicion of HPA-axis dysfunction your GP can't investigate via Medicare.
- Mast cell activation workup (tryptase, prostaglandins) if MCAS is being considered — usually requires a clinical immunologist referral.
Generally not worth paying for
- “Cytokine panels” — expensive ($300–$600), non-standardised, and can't guide treatment decisions in a clinical setting.
- “Microclot testing” — not validated, no agreed reference ranges, no proven treatment based on results.
- Mitochondrial function panels — interesting research, but no established clinical utility for individual patients in Australia.
- Heavy metal panels — very rarely the explanation for long COVID-like symptoms.
- Comprehensive food intolerance / IgG panels — not evidence-based for fatigue or brain fog.
Frequently Asked Questions
Is there a blood test that diagnoses long COVID?
No. There is no diagnostic blood test for long COVID. Diagnosis is clinical — based on persistent symptoms more than 12 weeks after a confirmed or suspected COVID-19 infection that cannot be explained by another cause. Blood tests are used to rule out alternative explanations for the symptoms.
What blood tests does the RACGP recommend for long COVID?
The RACGP recommends a baseline panel: full blood count (FBC), urea & electrolytes, liver function tests, C-reactive protein, ferritin, vitamin B12, folate, TSH, vitamin D, iron studies, and fasting glucose or HbA1c. Additional tests are guided by specific symptoms — for example, BNP/NT-proBNP and D-dimer if breathlessness, CK if muscle pain, ANA if joint pain or rash.
Are long COVID blood tests covered by Medicare?
Yes. The standard panel of tests used to investigate long COVID symptoms is covered by Medicare when ordered by a GP for clinical reasons such as fatigue, breathlessness, or cognitive symptoms. Most pathology providers bulk-bill these tests. Some specialised tests (cortisol stimulation, autonomic testing) may have an out-of-pocket cost.
How long should symptoms last before testing for long COVID?
WHO defines long COVID (post COVID-19 condition) as symptoms persisting for at least 2 months and starting within 3 months of a probable or confirmed COVID-19 infection, with no other explanation. Most GPs will start investigations once symptoms persist beyond 4-12 weeks.
What is POTS and how is it tested?
POTS (postural orthostatic tachycardia syndrome) is a common feature of long COVID, causing rapid heartbeat and dizziness on standing. The simplest test is the active stand test or NASA Lean Test: heart rate measured lying down, then on standing for 10 minutes. A heart rate increase of >30 bpm (or >40 in adolescents) within 10 minutes of standing, without a drop in blood pressure, suggests POTS.
Should I test for reactivated EBV or other viruses?
Testing for EBV (Epstein-Barr virus) and CMV reactivation may be useful if you have persistent fatigue, swollen lymph nodes, or sore throat — symptoms suggesting glandular fever-like illness. The evidence for reactivated viruses driving long COVID is still emerging. Discuss with your GP whether testing is worthwhile in your case.
Are there long COVID clinics in Australia?
Yes. Most state public hospitals have long COVID clinics, typically requiring a GP referral. Examples include the St Vincents Long COVID Clinic in Sydney, Royal Melbourne Hospital Long COVID Clinic, and Princess Alexandra Hospital in Brisbane. Wait times vary from weeks to many months. Some private GP practices specialise in long COVID care.
Should I get private specialty long COVID testing?
For most people, the standard Medicare-funded panel covers the important tests. Private specialty panels (cytokine profiles, mitochondrial function, microclot testing) are mostly experimental, expensive, and not validated for clinical decision-making in Australia. Spend the money on a comprehensive specialist consultation instead.
Related Reading
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Long COVID is an evolving area of medicine. This guide reflects the consensus position of Australian general practice and current published guidelines. It is not a substitute for individual medical advice. Always consult your GP or treating clinician for diagnosis and management of post-COVID symptoms.