CASE PRESENTATION: A 62-year-old woman with bipolar disorder and cerebral vascular accident presented with 3 days of headache, nausea/vomiting and altered mental status. She was hypertensive to 199/106 and not oriented to self/time/place/situation. Neurologic exam, CT head, electrolyte panel, and tox. screen were negative for abnormalities. Intentional lithium overdose was suspected as her initial serum lithium level was > 3.0 (therapeutic level 0.5-1.5mEq/L). She underwent emergent hemodialysis followed by continuous veno-venous hemodialysis. Repeat level showed <0.20 immediately afterwards and remained low subsequently. Investigation into a false positive result revealed that the original sample was collected in a lithium heparin containing tube - thus, falsely elevating the lithium level.