Lithium

Lithium

Epic Mnemonic
Sunquest Mnemonic

LAB29
LI

Category

Chemistry

Methodology

Colorimetric

Test Performance Schedule

Sunday - Saturday

Result Availability

Within 24 hours – STAT upon request

Container

Gold top (SST) or Red top (serum)
Alt: EDTA

Volume

Pref. Vol.: 1.0 mL serum

Min. Vol.: 0.5 mL serum

Collection Instructions

• Collect 12 hours after last dose

• Routine venipuncture

• Immediately after collection, gently invert tube 5-10 times

• Clot 30 minutes

• Promptly centrifuge

• If no gel barrier is present immediately transfer serum or plasma to a plastic tube and refrigerate

• Properly centrifuged gel barrier tube does not require transfer of serum or plasma to separate tube

Transportation Instructions

Refrigerated

Stability

• Room Temperature: 1 day

• Refrigerated: 5 days

Causes for Rejection

• Collected in Green top (Lithium heparin) tube

CPT Codes

80178

Effective/Revised

03/28/2017

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.

Levels higher than 1.5 mmol/L (12 hours after a dose) indicate a significant risk of intoxication.