Summary
| Direction in Long COVID | ↑ Elevated — higher than in the comparison group |
|---|---|
| Category | Metabolic |
| Also described as | Anaerobic metabolite |
| Compared against | HC (healthy controls) |
| Associated symptoms | Exercise intolerance, PEM |
| Test type | Blood test (serum / plasma / whole blood) |
| LOINC code | 2524-7 |
| Source | Baalbaki et al. 2025 — doi:10.1111/all.16526 |
| Condition atlas | Long COVID Biomarker Atlas |
Other conditions where Lactate is reported
- Lactate in Gulf War Illness — ↑ elevated vs HGV
- Lactate (blood) in ME/CFS — ↑ elevated vs HC
See the cross-condition hub: Lactate across conditions.
Trials, interventions and tests
In clinical-trial registrations this marker maps to the outcome term Changes in lactate (12 registered trials use a matching outcome measure).
Clinical trials using Lactate as an outcome
- NCT07278206: Brain Stimulation in Long COVID (Recruiting)
Outcome measure: Magnetic Resonance Spectroscopy (MRS) - NCT06840873: Tele-Rehabilitative Exercise Training Program in Nurses With Long COVID (Completed)
Outcome measure: Anaerobic threshold (AT in ml/kg/min) - NCT07046208: Effects os Physiotherapeutic Rehabilitation on Function Autonomic and Inflammatory in Patients With Long Covid (Not Yet Recruiting)
Outcome measure: Inflammation - NCT06967428: Effect of Metabolic Modulation on a Post-acute COVID-19 Vaccination Syndrome (PACVS) Cohort (Not Yet Recruiting)
Outcome measure: Sedentary blood lactate - NCT05922865: The Effect of Smart Sensor Combined With APP for Individualized Precise Exercise Training in Long Covid-19 (Completed)
Outcome measure: Anaerobic Threshold (mL/kg/min) - NCT04482595: BIO 300 Oral Suspension in Previously Hospitalized Long COVID Patients (Unknown)
Outcome measure: Change in Clinical Laboratory Values for Serum Enzymes - NCT05669261: Treatment of Long COVID Symptoms Utilizing Autologous Stem Cells Following COVID-19 Infection (Unknown)
Outcome measure: Assessment of Change in Lactate dehydrogenase (LDH) Laboratory Testing Results - NCT05152849: Efficacy, Safety, Tolerability of AXA1125 in Fatigue After COVID-19 Infection (Completed)
Outcome measure: Change from baseline in serum lactate level after a 6-minute walk test
4 more trials reference this marker.
Interventions studied alongside this marker
Hypothesis-generating links from trial outcome usage and literature co-occurrence. Not treatment recommendations.
- Repetitive Transcranial Magnetic Stimulation — 1 trial, 5 PubMed co-citations
e.g. Role of astrocyte in neuroinflammation-induced loss in neuroplasticity and subsequent onset of depression: A… - Wearable Device — 1 trial, 6 PubMed co-citations
e.g. Rethinking Lactate in Cardiac Surgery and Intensive Care. - N-acetylcysteine — 1 trial, 6 PubMed co-citations
e.g. [Spermine induces ferroptosis-related phenotype in acute myeloid leukemia cells through reactive oxygen… - Acupuncture — 1 trial, 6 PubMed co-citations
e.g. Acupuncture in ischemic stroke: from local neuromodulation to metabolic reprogramming.
Commercial test availability
Lactate (blood) — commercial laboratory test.
Links are for reference only; availability, specimen requirements and coverage vary by location.
Related Metabolic markers in Long COVID
- 4-Aminobutanoate (GABA) ↑
- Carnitine / Acylcarnitines ↕
- Xanthine ↑
- Thymine ↓
- Uracil ↓
- Porphobilinogen ↑
- 5-Aminolevulinate ↑
- Putrescine ↑
Full list: Long COVID Biomarker Atlas.
Frequently asked questions
Is Lactate high or low in Long COVID?
Elevated. Studies summarised in the OSMF atlas report higher Lactate in Long COVID than in healthy controls. Source: Baalbaki et al. 2025.
What symptoms is Lactate associated with in Long COVID?
The cited literature associates this marker with Exercise intolerance, PEM. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures Lactate?
It is measured as a blood test (serum / plasma / whole blood). The standard laboratory code is LOINC 2524-7. Commercial laboratories such as Quest Diagnostics, LabCorp, Ulta Lab Tests list an orderable assay.
Is one abnormal Lactate result diagnostic of Long COVID?
No. No single biomarker is diagnostic of Long COVID. Lactate findings come from group comparisons, overlap considerably between patients and controls, and vary with study design, timing and comparison group. A result should be interpreted by a clinician alongside symptoms, history and other tests.
Is Lactate specific to Long COVID?
No. The same marker is also reported in Gulf War Illness, ME/CFS in this atlas, so it reflects shared biology (for example inflammation or vascular stress) rather than a condition-specific signature.
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Last reviewed: 2026-06-29 · Page generated from long-covid.json · Browse: Long COVID atlas · Biomarker Index · All marker pages
Disclaimer: This page is an educational synthesis of published, peer-reviewed research and is not medical advice. Biomarker findings vary across studies with case definitions, comparison groups, timing and assay methods. Direction of change reflects the predominant finding in the cited source and does not establish a diagnostic threshold. Discuss any test result with a qualified clinician.