Lithium (take 12 hours after dose)
Private Lithium blood testing in London for £67, measuring the level around 12 hours after the dose for safe therapeutic drug monitoring.
Turnaround time
4 business days
Biomarkers count
1
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Overview of the Lithium Blood Test
The Lithium blood test measures the concentration of Lithium in the bloodstream and is used for therapeutic drug monitoring in people prescribed Lithium.
The test contains 1 biomarker: Lithium.
Lithium is used in the treatment and prevention of several mood disorders, particularly bipolar disorder.
It has a relatively narrow therapeutic range.
This means the difference between a concentration that is therapeutically useful and one associated with toxicity can be comparatively small.
Regular monitoring is therefore an essential part of safe Lithium treatment.
The timing of blood collection is critical.
For routine monitoring, the sample is conventionally taken approximately 12 hours after the most recent Lithium dose so that results can be compared with established treatment targets.
A level drawn substantially earlier or later may not be comparable and can lead to incorrect interpretation.
Lithium is eliminated predominantly through the kidneys.
Changes in kidney function, hydration, salt balance and certain interacting medicines can therefore alter the concentration even when the prescribed Lithium dose has not changed.
Vomiting, diarrhoea, dehydration and acute illness can increase toxicity risk.
Medicines including some NSAIDs, ACE inhibitors, angiotensin receptor blockers and thiazide diuretics can also raise Lithium concentrations in some patients.
A routine private result should support, not replace, the clinician responsible for prescribing and monitoring Lithium.
What Does the Lithium Test Check?
This test measures one therapeutic-drug concentration and is specifically timed to support safe interpretation of prescribed Lithium therapy. This test measures 1 biomarker.
Lithium
Measures the concentration of Lithium in blood approximately 12 hours after the most recent dose to support assessment of therapeutic exposure and toxicity risk.
Who May Benefit From the Lithium Test?
Lithium monitoring is primarily intended for people already receiving prescribed Lithium and may be required routinely or when treatment, health or medication circumstances change.
People currently taking prescribed Lithium - Regular blood-level monitoring forms an important part of safe long-term Lithium treatment.
People who have recently started Lithium therapy - Blood testing can help establish whether the prescribed regimen is producing an appropriate concentration once the medicine has reached a stable level.
People whose Lithium dose has recently changed - Repeat testing can assess how the new dose has affected the blood concentration.
People whose Lithium formulation or dosing schedule has changed - Changes in treatment can alter exposure and may require repeat monitoring.
People starting a medicine that can interact with Lithium - Certain medicines can reduce renal Lithium clearance and increase blood concentrations.
People stopping an interacting medicine - The Lithium concentration can also change after another treatment is withdrawn.
People with changing kidney function - Because Lithium is primarily cleared by the kidneys, impaired renal function can increase accumulation.
People who have recently experienced dehydration - Significant fluid loss can raise Lithium concentrations and increase toxicity risk.
People who have had vomiting or diarrhoea - Gastrointestinal illness can cause both fluid and Sodium changes that affect Lithium handling.
People experiencing new side effects while taking Lithium - Blood-level measurement may help determine whether excessive drug exposure is contributing.
People undergoing routine long-term treatment monitoring - Regular testing helps confirm that concentrations remain appropriate as health, medication and physiology change over time.
How to Prepare
Correct timing is essential. A result taken six hours after a dose should not be interpreted in the same way as a properly timed 12-hour result.
Do not stop Lithium or alter the prescribed dose unless instructed by the clinician managing your treatment.
If significant Lithium toxicity is suspected, urgent clinical assessment is more appropriate than waiting for routine outpatient monitoring.
Symptoms and Reasons to Consider the Lithium Test
People taking Lithium may need additional testing when new symptoms develop, particularly if they follow dehydration, illness, a dose change or the introduction of another medicine.
Increasing or unusually coarse tremor - A fine tremor can occur during Lithium treatment, but a worsening or coarse tremor can be associated with excessive exposure.
Persistent nausea - Gastrointestinal symptoms can occur when Lithium concentrations become too high.
Vomiting - Vomiting may be both a symptom of Lithium toxicity and a cause of dehydration that further increases Lithium concentration.
Diarrhoea - Diarrhoea can accompany toxicity and can also worsen Lithium accumulation through fluid and electrolyte loss.
Increasing drowsiness - Unusual sleepiness or reduced alertness can occur with clinically significant toxicity.
Confusion or altered thinking - New neurological or cognitive changes require prompt assessment in someone taking Lithium.
Poor coordination or unsteadiness - Difficulty walking steadily or coordinating movements can be an important warning sign of neurological toxicity.
Slurred speech - This can occur with significant Lithium toxicity and requires urgent medical assessment.
Markedly increased thirst - Lithium can affect the kidneys' ability to concentrate urine, resulting in increased thirst.
Frequent urination - Persistent polyuria can occur during Lithium treatment and may warrant kidney and electrolyte assessment.
Symptoms developing after dehydration or illness - Lithium concentrations can rise even when the prescribed dose has not changed.
Symptoms beginning after a new medication is introduced - Drug interactions can alter Lithium clearance and increase toxicity risk.
Symptoms of Lithium toxicity can progress and become medically serious.
Significant confusion, severe tremor, marked unsteadiness, repeated vomiting, slurred speech, seizures, reduced consciousness or other substantial neurological symptoms require urgent medical assessment rather than waiting for routine private test results.
A Lithium blood result should support clinical decision-making and should not be used independently to change treatment.
How to Book Your Lithium Test
Booking the Lithium blood test with London Blood Tests is straightforward, although the appointment should be planned carefully around the timing of your normal Lithium dose.
Choose the Lithium
Select the individual Lithium therapeutic drug monitoring blood test online.
Select your sample collection option
Choose an in-clinic blood draw or professional home or hotel phlebotomy appointment that allows the specimen to be collected approximately 12 hours after your most recent Lithium dose.
Attend your appointment
A trained healthcare professional collects the required venous blood specimen, and the exact dose and timing information should be recorded.
Laboratory analysis
Your blood sample is analysed to determine the concentration of Lithium circulating in the bloodstream.
Receive your results securely
Your authorised Lithium result is delivered securely and should be reviewed with the clinician responsible for prescribing and monitoring your treatment.
When Will I Receive My Results?
The current expected turnaround time for the Lithium test is approximately 4 days after your sample reaches the laboratory.
The laboratory measures the Lithium concentration and completes the necessary analytical quality-control and result-authorisation procedures before reporting.
The turnaround begins from laboratory receipt rather than necessarily from the exact time at which your blood is collected.
Courier schedules, weekends, bank holidays, specimen issues or the occasional need to repeat an analysis can extend the overall reporting period.
The clinical usefulness of the result depends not only on the laboratory turnaround but also on whether the blood specimen was collected at the correct interval after the preceding Lithium dose.
If the timing is substantially different from approximately 12 hours, the prescribing clinician should be told because this may change how the concentration is interpreted.
A routine four-day turnaround is not appropriate for suspected acute Lithium toxicity. If significant symptoms of toxicity are present, urgent medical assessment and appropriately rapid Lithium testing should be sought instead.
Understanding Your Results
Your report will show the concentration of Lithium measured in the blood, usually reported in mmol/L.
Lithium should not be interpreted using one universal target for every patient.
The appropriate therapeutic concentration depends on factors including the reason for treatment, whether therapy is being used for acute treatment or maintenance, age, response to therapy, side effects and the treatment plan established by the prescribing clinician.
A result below the individual's intended therapeutic target may indicate that Lithium exposure is lower than required.
However, an apparently low result can also occur if the sample was collected much later than the intended 12-hour interval, if doses have been missed or if treatment has recently changed.
A result within the treatment range established by the prescribing clinician suggests that the measured concentration is consistent with the intended therapeutic exposure at that point in treatment.
This does not mean that monitoring is no longer required. Lithium levels can change over time because of kidney function, hydration, age, illness and medication interactions.
A result above the individual's intended range raises concern about excessive Lithium exposure and an increased risk of adverse effects or toxicity.
The clinical significance depends on the actual concentration, symptoms and circumstances.
Timing is critical. A concentration obtained soon after a dose is expected to be higher than a properly timed 12-hour level and should not be interpreted using the same therapeutic framework.
When a previously stable Lithium level changes unexpectedly, clinicians may also review Creatinine, eGFR, Urea, Sodium, hydration status, medication interactions and recent illness.
Lithium results should therefore be interpreted as part of ongoing therapeutic monitoring rather than as an isolated laboratory number.
Why Book With London Blood Tests?
Lithium requires careful therapeutic monitoring because blood concentrations can change with kidney function, hydration, illness and medication interactions.
Dedicated Lithium monitoring - Measures the concentration of prescribed Lithium directly in the bloodstream.
Appropriate 12-hour monitoring guidance - The importance of collecting the specimen at approximately the correct interval after the dose is recognised.
Useful after dose changes - Repeat testing can determine how a revised treatment regimen has affected Lithium exposure.
Relevant after medication changes - Monitoring may be particularly useful when interacting medicines are started or stopped.
Important during illness or dehydration - Lithium concentrations can change substantially when fluid or Sodium balance is disturbed.
Supports long-term treatment safety - Regular monitoring helps identify unexpectedly high or low concentrations.
Relevant to kidney health - Lithium is predominantly eliminated through the kidneys, making renal function an important part of ongoing treatment monitoring.
Professional phlebotomy - Timed venous sample collection can be arranged through London Blood Tests.
Clinic and home collection options - Blood collection can be arranged according to location and suitability while respecting the required dose-to-sample interval.
Secure reporting - Receive your authorised laboratory result confidentially.
Clear pricing - The Lithium blood test costs £67.
Private Lithium Blood Test in London
London Blood Tests provides private Lithium therapeutic drug monitoring in London for people who are prescribed Lithium and require routine or additional blood-level assessment.
The test costs £67 and measures 1 biomarker: Lithium.
The blood sample should generally be collected approximately 12 hours after the most recent Lithium dose, unless the clinician responsible for treatment has provided different instructions.
Results are expected approximately 4 days after laboratory receipt.
The result should be interpreted alongside the exact dose, timing of the previous dose, kidney function, hydration, medication interactions, symptoms and previous Lithium measurements.
Private Lithium testing can be useful for routine monitoring, following treatment changes or when an additional level has been requested, but prescribing decisions should remain under the supervision of the clinician responsible for Lithium therapy.