Understanding lithium lab results

Hi @annedallas

I ran it by Claude.ai and this is the response

MY query: A person's lab results were reported as follows " showed his lithium level to be "under 0.3 L" and the reference range to be "0.6-1.2 mmol/L". Since the other values are in mmol/L, is the "under 0.3 L" an error?

Claude's answer:
"Yes, almost certainly a transcription or reporting error.
Here's why:
"L" alone is not a valid unit for a blood concentration. Lithium levels are always reported as a concentration — meaning an amount of substance per volume of fluid. The standard units used are:
- mmol/L (millimoles per litre) — most common internationally
- mEq/L (milliequivalents per litre) — used in some US labs; numerically identical to mmol/L for lithium
- mg/L or mg/dL — less common but used in some settings
"L" alone (just "litres") is a unit of volume, not concentration, and makes no scientific sense for a blood test result.

Most likely explanation
The "L" is almost certainly a truncation of "mmol/L" — the units were cut off, leaving only the last character. This is a common artifact when:
- Results are copied from an electronic health record (EHR) into a report or note
- A table or field cuts off text
- Manual transcription omits part of the unit
So "under 0.3 L" should most likely read "under 0.3 mmol/L", which is consistent with the reference range units and makes clinical sense.

Bottom line
The value itself (< 0.3) is interpretable and clinically meaningful as discussed previously — subtherapeutic — but the unit as written is an error and should be corrected in the record for accuracy and safety. If this appears in a formal document, it would be worth flagging for correction."

So. Check with the doc, but it seems like your LO is most likely 0.3 mmol/L under the lower end of the target range.

@annedallas wrote: "...lithium level to be "under 0.3 L" and the reference range to be "0.6-1.2 mmol/L"..."

@memoriestomoments helpfully replied: "...LO is most likely 0.3 mmol/L under the lower end..."

I'm quite surprised to see no further discussion about this. Many comments here on Mayo Connect address the chance that Lithium level in the brain may both cause and cure MCI and Alzheimer's (see the other Connect topics and google this: harvard 2025 alzheimer's).

Having read the two comments above, I'm curious if Lithium Orotate (LiO) dose could be adjusted based on the target range. I was unclear whether the fluid mentioned is blood or spinal fluid, so I asked Google Gemini and got this:
"A target range of 0.6 - 1.2 mmol/L (often also expressed as mEq/L) refers to blood (specifically serum or plasma) when monitoring the concentration of the medication lithium. This specific range is used for psychiatric maintenance therapy to ensure the drug is effective at stabilizing mood while avoiding dangerous toxicity. The optimal target within this window depends on the individual and the condition being treated."

I find it very interesting that taking 20 mg a day LiO resulted in blood lithium below the normal range! I read that the blood draw should be done 10-12 hours after the last dose. How much does it fluctuate? Are those of us taking it taking the right dose? I believe the "mouse data" translated to human dosage was 12 mg per day. My LO has an appt with her neurologist in Oct. I'm going to request a blood test. She's been taking 10 mg a day for 11 months with no improvement in her condition. In fact her short term memory has continued to deteriorate. Are there reports from anyone else?

Hi. My LO gets his LiO at bedtime, so his blood draw (that yielded the <.3 results) was done more than 12 hours after dosage----who knows if that's significant. The earlier draw (when it was <.1 and he was getting 5mg versus 20) was done with the same timing.
He continues to decline; it's impossible to know how much he would have declined, absent the lithium. But I see no adverse effects whatsoever. So despite it not being a "fix", we'll continue to do it.

What we may be seeing is an example of mouse data not translating to humans. If I'm not mistaken, in the recent Harvard study alz was not only stopped, it was reversed. Like you we'll continue taking LiO because it's our only near term hope.

@longboat1 You might want to consider getting your LO's lithium level tested. You can do it without a doc's orders (at least in Texas) at Quest and presumably LabCorp; it's not expensive. It was learning that my husband's level was so low that prompted us (with guidance from his internist son) to increase to 20 mg.