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Test Code LI Lithium LAB29

Performing Laboratory

UnityPoint The Finley Hospital

Test Method

Spectrophotometric; Roche cobas Pro

Performance

Testing is performed Monday through Sunday.

Routine orders: Typically completed within 4 hours

STAT orders: Typically completed within 45 minutes after
the specimen arrives at the testing site.

Specimen Requirement

Serum (red) or EDTA plasma:(purple) 0.5 mL. Gel tubes are not acceptable.

It is recommended that the serum or plasma be separated from contact with cells within 2 hours from time of collection.

Lithium samples are stable for 24 hours at 20-25ºC, 7 days at 2-8ºC, and 6 months at -15ºC. 

Useful For

Lithium is widely used in the treatment of manic depressive psychosis. Administered as lithium carbonate, it is completely absorbed by the gastro‑intestinal tract; peak serum levels occur 2 to 4 hours after an oral dose. The half life in serum is 48 to 72 hours and it is cleared through the kidneys (excretion parallels that of sodium). Reduced renal function can prolong clearance time.

Lithium acts by enhancing the uptake of neurotransmitters, which produces a sedative effect on the central nervous system. Serum lithium concentrations are measured essentially to ensure compliance and to avoid toxicity. Early symptoms of intoxication include apathy, sluggishness, drowsiness, lethargy, speech difficulties, irregular tremors, myoclonic twitchings, muscle weakness and ataxia.

Reference Values

  1. Therapeutic range: 0.6-1.2 mmol/L.
  2. Critical value: greater than (>)2.0 mmol/L

CPT Code Information

80178 Therapeutic Drug Level: Lithium

LOINC Code Information

14334-7 Lithium [Moles/Volume] In Serum Or Plasma