Coenzyme Q10 (CoQ10) Test
The CoQ10 test measures plasma coenzyme Q10, a mitochondrial electron carrier and antioxidant. It identifies primary or secondary deficiency states — including statin-induced depletion, rare genetic biosynthetic defects, and depletion in heart failure or mitochondrial disorders — and monitors therapeutic supplementation.
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Biomarkers
Blood (serum)
Sample
3–7 business days
Turnaround
Preferred but not mandatory
Fasting
What is the CoQ10 test?
The Coenzyme Q10 Test measures plasma concentration of an essential mitochondrial electron carrier and antioxidant. Practitioners order it to investigate suspected deficiency in patients with unexplained myopathy, fatigue, or mitochondrial dysfunction, and to screen individuals on statin therapy who report muscle symptoms. Because tissue CoQ10 stores far exceed circulating levels, a low result points to systemic depletion, while a normal result does not exclude localised or subclinical insufficiency. CoQ10 sits at the intersection of energy metabolism and oxidative stress, so the test is used in cardiovascular, neurological, and metabolic contexts — evaluating statin myalgia, supporting the work-up of suspected primary CoQ10 deficiency or broader mitochondrial disease, and monitoring supplementation. It is rarely diagnostic in isolation but adds weight when combined with symptom patterns, medication history, and in some cases muscle biopsy or genetic testing.
What does the CoQ10 test measure?
Coenzyme Q10 is a lipophilic benzoquinone synthesised endogenously in mitochondria and also obtained from dietary sources. It shuttles electrons in the mitochondrial respiratory chain, couples oxidative phosphorylation, and acts as a membrane-bound antioxidant in its reduced form (ubiquinol). Plasma CoQ10 circulates largely within lipoproteins, and tissue concentrations — particularly in heart, kidney, and liver — are far higher than those in blood. Endogenous synthesis declines with ageing and certain chronic diseases.
Serum CoQ10 is measured to identify deficiency states — primary (rare genetic biosynthetic defects) or secondary (statin-induced depletion, mitochondrial disorders, heart failure, and potentially neurodegenerative conditions). Because the test reflects circulating rather than tissue levels, interpretation requires clinical context: symptomatic myopathy or fatigue in a statin-treated patient, evaluation of suspected mitochondrial disease, or monitoring of therapeutic supplementation. Plasma CoQ10 does not predict cardiovascular or neurological outcomes in isolation but guides replacement therapy.
Why is the CoQ10 test ordered?
- Investigation of statin-associated muscle symptoms (myalgia, cramps, weakness) not explained by creatine kinase elevation alone
- Evaluation of suspected primary CoQ10 deficiency in patients with childhood-onset encephalomyopathy, ataxia, or multisystem disease
- Work-up of mitochondrial disorders, interpreted alongside lactate, pyruvate, and organic acids, and in conjunction with specialist referral
- Assessment of patients with heart failure, where low CoQ10 has been associated with worse functional status and where supplementation trials have shown modest benefit
- Monitoring of therapeutic CoQ10 supplementation to confirm adequate absorption and guide dosing adjustments
- Consideration in patients with neurodegenerative conditions (Parkinson disease, ataxia) as an adjunct to standard investigations, recognising the exploratory nature of this indication
- Screening in patients on high-dose statin therapy with a history of exercise intolerance or fatigue, particularly when dose reduction is undesirable
Sample collection and turnaround
Sample type
Blood (serum)
Fasting required
Preferred but not mandatory
Collection method
Venipuncture at patient service centre
Turnaround
3–7 business days
Collection notes
Phlebotomy at the processing laboratory draw site (LabCorp, Access Medical Laboratories, or Boston Heart Diagnostics, depending on routing). Fasting improves consistency by minimising postprandial variability. If assessing baseline endogenous status, instruct patients to discontinue CoQ10 supplements for 48–72 hours before the draw. Protect specimen from prolonged light exposure.
Specimen requirements
Minimum 1 mL serum. Separate from cells promptly and protect from light. Freeze if not analysed within 24 hours. Note the performing laboratory and assay method for serial comparability.
What can affect CoQ10 results?
Oral supplementation raises plasma CoQ10 in a dose-dependent manner; discontinue supplements for at least 48–72 hours before testing if baseline endogenous status is the clinical question.
HMG-CoA reductase inhibitors block the mevalonate pathway, reducing endogenous CoQ10 synthesis. The degree of depletion varies by statin type, dose, and duration.
CoQ10 circulates bound to lipoproteins, so low cholesterol (whether primary or drug-induced) can lower plasma CoQ10 independently of tissue stores. Total and LDL cholesterol should be considered when interpreting results.
CoQ10 is present in meat and fish; a large meal shortly before the draw may modestly raise circulating levels. Fasting is not mandatory but improves consistency.
CoQ10 assays (HPLC with electrochemical or UV detection, LC-MS/MS) differ in sensitivity and whether they measure total CoQ10 or separate ubiquinone and ubiquinol fractions. Prolonged light or air exposure can degrade the sample.
Endogenous CoQ10 synthesis declines with ageing, heart failure, diabetes, and possibly neurodegenerative disease, so lower values may reflect the underlying condition rather than a distinct deficiency state.
What do CoQ10 results mean?
Elevated
Elevated CoQ10 is almost always due to supplementation and is not pathological. Rarely, very high values may indicate assay error or specimen mishandling, and should be confirmed with a repeat sample if clinically unexpected.
Normal
A normal plasma CoQ10 does not exclude tissue-level insufficiency, particularly in mitochondrial myopathies where muscle CoQ10 may be depleted while blood levels remain in range. Interpret in the context of the presenting complaint and other metabolic or mitochondrial markers.
Reduced
Low plasma CoQ10 may indicate: statin-induced depletion (the most common cause in adults); primary CoQ10 deficiency (rare, usually presenting in childhood with encephalomyopathy, ataxia, renal disease, or multisystem involvement); secondary depletion in heart failure, mitochondrial disorders, or severe malabsorption; or artefactually low values due to low lipoprotein levels. Correlate with the medication list, symptom chronology, creatine kinase, and lipid profile, and consider trial supplementation (typically 100–300 mg daily ubiquinol or ubiquinone) with reassessment of symptoms and repeat testing.
Note: CoQ10 results are assay-dependent, and reference intervals differ between laboratories. Serial monitoring should use the same performing lab. Plasma CoQ10 is a surrogate for tissue stores; muscle biopsy measurement may be required in suspected primary deficiency. Because circulating CoQ10 tracks with lipoproteins, interpret alongside the lipid panel. The test guides supplementation decisions rather than diagnosing a specific disease entity.
Frequently asked questions
Statins inhibit the mevalonate pathway, reducing endogenous CoQ10 synthesis. Testing identifies depletion in patients with muscle symptoms (myalgia, cramps, weakness) that are unexplained by creatine kinase alone, and guides supplementation to alleviate symptoms without discontinuing the statin.
How to access the CoQ10 test
The CoQ10 reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.
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Published: October 7, 2026
Last reviewed: October 7, 2026
- Littarru GP, Tiano L. Clinical aspects of coenzyme Q10: an update. Nutrition. (2010)
- Mortensen SA, et al. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO. JACC Heart Fail. (2014)
- Banach M, et al. Statin intolerance — an attempt at a unified definition. Position paper from an International Lipid Expert Panel. Arch Med Sci. (2015)
- Quinzii CM, et al. Primary coenzyme Q10 deficiency. GeneReviews (University of Washington). (2014)
- Hathcock JN, Shao A. Risk assessment for coenzyme Q10 (ubiquinone). Regul Toxicol Pharmacol. (2006)
This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.