Lithium is neither metabolized nor protein bound, thus its bioavailability is close to 100%. Lithium absorption is rapid and it has a narrow therapeutic index. Several factors might lead to impairment in lithium secretion. It has recognised adverse effects on renal and thyroid function.
Lithium
Lithium
Lithium can be used in psychiatric treatment indicated for the prophylaxis and treatment of mania in bipolar disorder and is sometimes used as an augmentation strategy for patients with treatment-resistant depression.
Sodium and volume depletion due to any conditions like vomiting, diarrhoea, febrile illness, renal insufficiency, excessive exercise, water restriction, excessive sweating, low sodium diet, and congestive heart failure may enhance lithium reabsorption in the kidneys. Furthermore, drugs reducing the glomerular filtration rate might inflict chronic toxicity. The kidneys treat lithium and sodium similarly which is the reason sodium depletion can significantly elevate lithium reabsorption. Serum lithium concentrations are monitored to assure patient compliance and to avoid intoxication. Early symptoms of intoxication include drowsiness, speech difficulties and twitching.
According to the Irish Medication Safety Network, Best Practice Guidelines on Lithium Prescribing, they advise that a serum sample should be taken 12 hours after the last dose to get a more accurate serum level. They also recommend that the minimum effective plasma level for prophylaxis is 0.4mmol/L with the optimal range being 0.6-0.75 mmol/L and that toxic effects reliably occur at levels >1.5mmol/L. Levels should be checked every 3 months routinely, with increased testing at initiation and if any dose adjustments are made to ensure levels are within normal range.
https://imsn.ie/wp-content/uploads/2019/11/imsn-lithium-guidelines-may-2012.pdf
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5mL venous serum or plasma (Sodium heparin K2 EDTA)
Enfer Medical
Tests/Assays
Enfer Medical offers Spectrophotometric technology for the quantitative assay for Lithium. This test is CE-IVD certified.
Patient
Request Form
For clients using the Enfer Medical Client Portal, the Enfer Medical Patient Request Form (PRF) will be generated when you have completed your “Test Request” within the portal linked below.
Please note that samples suspected of containing high risk pathogens such as Mycobacterium tuberculosis should be clearly identified on the form and packed separately from other samples.
Results are available next working day.
This assay is available seven days a week.
Packaging
The packaging/preparation of samples for delivery to the laboratory are required to be in adherence to all national regulations for the safe transport of biological materials. HSE guidance can be reviewed HERE.
There are specific packaging instructions and labelling requirements requiring triple packaging including:
- Primary leak-proof container – tube or vial containing the sample.
- Secondary watertight container, with absorbent material, intended to protect the primary container.
- Outer container protects the secondary container.
- Patient Request forms must be placed between the secondary container and the outer shipping container.
Further information on the packaging/preparation of samples for delivery to the laboratory is contained within the Enfer Medical Laboratory User Manual which clients are provided with.
Storage & Stability
Specimens must be tested within 7 days of collection and stored at 2-8°C.
Samples
In addition to the packaging of samples, the transport/delivery of clinical samples to the laboratory is required to be in adherence to all national regulations for the safe transport of biological materials. Enfer Medical provides a fully compliant logistics service, aligned with clients’ testing requirements.
Prompt transport of specimens:
To ensure prompt testing of samples and release of results within the published test turnaround times, samples should arrive to the laboratory by 18:00. Test turnaround time is measured from receipt of the sample at the laboratory until the time the authorised results are reported to users.
of Samples
In rare cases specimens may not be suitable for testing on arrival to the laboratory. In that case the sample will be rejected at the receipt stage and the service user will be notified immediately and an explanation as to why the sample could not be processed will be provided. Reasons why samples cannot be processed include but are not limited to:
- Samples received beyond the stability limits and/or not at the correct temperature indicated for each test.
- Incorrect sample type received.
- Leaking samples, sample not received or sample insufficient for analysis as stated below within sample requirements.
- Non-compliant samples or request forms i.e. those missing sample date information, missing sample test request and/or missing sample site/type information.
- Samples received without the necessary patient identifiers.
Our Services
Quantitative results for Lithium are reported in numeric value in mmol/L. Please contact us for more information on the reference ranges used at Enfer Medical.
Critical results are communicated in accordance with the Communication of critical results for patients in the community- national laboratory handbook CSP041/2019
Accessing
Your Results
Following receipt at the Laboratory, results should be available on the next working day and will be reported to the referring clinician via the Enfer Medical Client Portal or in a format agreed with clients.
Established clients can login to the portal using the link above.