| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Lithium, Serum
Test CodeLI - NOCO
CPT Codes
80178
Preferred Specimen
1 ml serum from Serum Gel or Red Top
Minimum Volume
0.5 mL
Instructions
- Draw a minimum of 12 hours after last dose (trough specimens).
- Peak serum concentrations do not correlate with symptoms.
Specimen Stability
| Specimen Type | Temperature | Time |
| Serum SST | Refrigerated | 7 days |
| Red Top – Separated* | Refrigerated | 7 days |
*Centrifuge and aliquot into a plastic vial.
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis
Methodology
Bichromatic Endpoint
Setup Schedule
Monday through Sunday; Continuously
Report Available
Same day
Reference Range
Therapeutic concentration: 0.6-1.2 mmol/L (trough concentration)
Critical value (automatic call-back): >1.5 mmol/L
Critical value (automatic call-back): >1.5 mmol/L
Clinical Significance
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.
Performing Laboratory
McKee Medical Center Laboratory
North Colorado Medical Center Laboratory
