Is a Lithium Level (Serum) worth it?
What it costs, whether to test at home or at Quest or Labcorp, and how to read your results.
Medically reviewed by Youmna DiStefano, MD — updated August 2026
The short answer
Yes if you take lithium — this is not an optional wellness test but the standard safety monitoring for a medication with a narrow therapeutic window: the blood level where lithium works and the level where it becomes toxic are close together. That's why it's monitored with blood tests rather than by how you feel, and why WHEN the sample is drawn matters as much as the number that comes back. At $29 it's far cheaper than the $90-120 the same draw bills elsewhere — but it is not a substitute for the monitoring schedule your prescriber sets; it's the affordable way to keep up with it.
Who should order it (and who can wait)
Worth it if you...
- •People on lithium whose prescriber ordered periodic levels but whose lab benefit or copays make each draw expensive
- •People who lost insurance coverage mid-treatment and need to keep monitoring going
- •Travelers and seasonal residents who need a level away from their home health system
You can probably wait if you...
- •You're not taking lithium — the level means nothing otherwise
- •Your prescriber wants the draw at a specific timing you can't hit that day: lithium levels are interpreted as a 12-hour trough (drawn about 12 hours after your last dose, before the next one), and a mistimed level can look perfectly reasonable while being wrong
- •You're trying to adjust your own dose from the result — dose decisions belong to your prescriber, full stop
We would rather you order the right test than the most expensive one.
At-home vs Quest vs Labcorp
The most common question we get. The short version: the lab and the result are the same - you are choosing where the blood is drawn.
Walk into a lab
Get drawn at any Quest or Labcorp location - thousands nationwide, often same-day. Best for speed and lowest cost.
At-home draw
Not recommended for this test - it needs a lab-based collection to be accurate.
Same result
Whichever you pick, it is run on the same CLIA-certified analyzers with the same reference ranges.
Not available at home, deliberately. Lithium levels are interpreted as a 12-hour trough with tight timing, and mobile phlebotomy arrival windows span hours — a mismatch that breaks the whole basis of interpretation. A patient service center with a fixed morning appointment preserves the timing at no real cost, since a morning draw is what the trough convention needs anyway (for a once-daily evening dose, about 12 hours later means morning). Record the exact date and time of your last dose and bring it to the draw. Ask your prescriber how they want the timing handled before you schedule — do not change or skip a dose to hit a window.
How to read your results
The markers that matter most and what an out-of-range value can mean. Reference ranges vary by lab, age, and sex.
| Marker | Typical range | What it means |
|---|---|---|
| Lithium level | Commonly cited maintenance range: roughly 0.6-1.0 mmol/L (some references use 0.4-1.0; lower targets around 0.4-0.8 are often used in older adults, higher around 0.8-1.2 for acute treatment). Your target is set by your prescriber, not by the lab's reference interval. | Risk of toxicity rises meaningfully above about 1.5 mmol/L; above 2.0 is serious. A result 'in range' for the lab may not be right for you — prescribers deliberately target different levels for different people and situations. Toxicity can also occur at levels that look normal, more often in older adults, during dehydration or illness, with reduced kidney function, and with medications including NSAIDs, ACE inhibitors, ARBs, and thiazide diuretics. |
Frequently asked questions
Ready to order your Lithium Level (Serum)?
$29.00, physician-authorized, results in 2–4 business days. No insurance or doctor's visit required.
About this guide
Reviewed August 4, 2026. This is general health information, not medical advice, diagnosis, or treatment. Reference ranges vary by laboratory, age, sex, and clinical context - always interpret results with a qualified healthcare provider. Lab analysis is performed at CLIA-certified Quest Diagnostics and Labcorp facilities.