Enter laboratory and treatment details
Use the reference interval printed on the laboratory report whenever available.
Current-tab calculation history
| Time | Total | Free | Ratio | Timing |
|---|---|---|---|---|
| No calculations saved in this browser tab. | ||||
Formula used
µg/mL = mg/L µg/mL = (µmol/L × 144.21 g/mol) ÷ 1000 µmol/L = (µg/mL × 1000) ÷ 144.21 g/mol Total daily dose = dose per administration × doses per day Dose by weight = total daily dose ÷ weight in kilograms Free-to-total percentage = (free level ÷ total level) × 100
The molecular weight used for valproic acid is 144.21 g/mol. No albumin-correction equation is used because calculated free levels can be unreliable.
How to use this calculator
- Select whether the report contains total, free, or both levels.
- Enter the measured concentration and choose its printed unit.
- Select a reference profile, then match limits to the laboratory report.
- Add sample timing, dose, formulation, weight, and albumin when known.
- Select relevant safety flags and list other medicines for clinical review.
- Calculate, then print, copy, or export the summary for discussion.
- Never adjust medication from this calculator without the prescriber.
Example data table
| Example | Total | Free | Timing | Configured ranges | Illustrative output |
|---|---|---|---|---|---|
| Both values entered | 82 µg/mL | 10 µg/mL | Trough | Total 50–100; free 5–25 | Both within selected ranges; free fraction 12.2% |
| High total flag | 132 µg/mL | Not entered | Random | Total 50–125 | Above range; timing limits interpretation |
| Low albumin context | 68 µg/mL | 18 µg/mL | Trough | Editable laboratory limits | Review measured free level and albumin clinically |
Understanding valproic acid level results
Valproic acid testing measures medicine circulating in blood. Total testing includes protein-bound and unbound medicine. Free testing measures the unbound portion directly.
The free portion is pharmacologically active and clinically important. Protein binding changes with albumin, illness, age, and medicines. Therefore, equal total levels may not produce equal effects.
Reference ranges are guides rather than universal treatment targets. Laboratories may use different methods and reporting intervals. A prescriber also considers response, adverse effects, and indication.
Blood collection timing can change the reported concentration substantially. Trough samples are commonly collected before the next dose. Peak or random samples require different clinical context.
Formulation also affects concentration patterns throughout each dosing interval. Extended-release products usually produce smoother changes than immediate products. Missed doses or recent changes complicate level interpretation.
A result below range does not automatically require more medicine. Adherence, collection timing, and clinical control need review. Some people respond outside a commonly listed interval.
A result above range does not prove clinical toxicity. However, symptoms or critical laboratory results require prompt assessment. Severe drowsiness, confusion, vomiting, or breathing problems need urgency.
Albumin reduction can increase the unbound fraction of valproate. A normal total result may then appear falsely reassuring. Direct free measurement is preferable to uncertain mathematical correction.
Daily dose per kilogram provides useful descriptive context only. It cannot identify an appropriate replacement dose for someone. Individual dosing depends on diagnosis, formulation, interactions, and monitoring.
Liver disease requires careful professional evaluation during valproate treatment. Pregnancy introduces serious fetal risks and complex treatment decisions. Neither situation should be managed through automated results.
Symptoms always deserve attention even when numbers appear acceptable. Sedation, tremor, stomach symptoms, or behavioral changes need timely review. Laboratory values should support assessment, never replace careful clinical evaluation.
Other medicines can increase or decrease valproate concentrations unexpectedly. Some interactions also change bleeding, sedation, or liver risks. Bring a complete medicine list to every clinical discussion.
Children, older adults, and acutely ill patients need individualized interpretation. Hydration, nutrition, and organ function may shift protein binding significantly. Repeat testing may be necessary when circumstances or treatment safely change.
This calculator keeps laboratory limits editable for safer comparison. It converts common units and displays transparent formulas. It also separates measured results from interpretive screening flags.
Share the complete result with a clinician or pharmacist. Include symptoms, dose times, missed doses, and recent changes. Professional review remains essential for every medication decision made.
Frequently asked questions
What is a total valproic acid level?
It measures both protein-bound and unbound valproate in the blood sample.
What is a free valproic acid level?
It measures the unbound fraction that is available to produce pharmacologic effects.
Why does sample timing matter?
Concentrations change after each dose, so peak, trough, and random results are not directly interchangeable.
Are 50–100 and 50–125 both valid ranges?
They are published reference approaches for different contexts. Use the range supplied by the laboratory and clinician.
Why is albumin included?
Low albumin may increase the free fraction and weaken the relationship between total level and active drug.
Does this calculator estimate a corrected level?
No. It intentionally avoids an albumin-correction formula and favors a directly measured free level.
Can this calculator diagnose valproate toxicity?
No. Toxicity assessment requires symptoms, examination, laboratory context, timing, and professional judgment.
Can I change my dose using this result?
No. Contact the prescriber because abrupt stopping or unsupervised changes can cause serious harm.
What should I do after a suspected overdose?
Use emergency services or a poison center immediately rather than waiting for an online calculation.
Where is calculation history stored?
History stays temporarily in session storage for the current browser tab and is not sent to a database.
Clinical references and limitations
This educational implementation uses editable defaults from established references. Laboratories and clinicians may use different limits.
- FDA prescribing information: commonly considered total epilepsy range of 50–100 µg/mL
- Mayo Clinic Laboratories: general total 50–125 µg/mL and free 5–25 µg/mL guidance
- Mayo Clinic Laboratories critical-values list
- PubChem: valproic acid molecular weight
- MedlinePlus valproic acid safety information
Disclaimer: This page is not medical advice, a diagnostic device, or a dosing tool. Emergency symptoms, pregnancy concerns, liver problems, pancreatitis symptoms, or suspected overdose require direct professional care.