{"id":"phenobarbital","name":"Phenobarbital","shortName":"Phenobarbital","aliases":["Luminal","Phenobarbital Level","Phenobarbitone","Phenobarbital, Serum","Phenobarbital, Total","Phenobarbital Serum Level","Phenobarb"],"abbreviations":["PHB"],"loinc":[{"code":"3948-7","primary":true},{"code":"14874-2","primary":false},{"code":"114382-5","primary":false},{"code":"114381-7","primary":false},{"code":"60468-6","primary":false}],"specimen":"serum-or-plasma","units":[{"ucum":"ug/mL","display":"mcg/mL"},{"ucum":"mg/L","display":"mg/L"},{"ucum":"umol/L","display":"µmol/L"}],"referenceRanges":[{"population":"Adults","low":15,"high":40,"unit":"ug/mL","unitDisplay":"mcg/mL","note":"Therapeutic range for people taking phenobarbital, not a healthy-population interval. ARUP prints 15 to 40 mcg/mL for ages 3 months and older (15 to 30 for 0 to 2 months), the same as one published hospital list; a Western India hospital uses 10 to 40. Individual response varies and tolerance can develop with long-term use, so the number is a guide rather than a cutoff.","sources":[{"title":"Phenobarbital (test 0090230)","url":"https://ltd.aruplab.com/Tests/Pub/0090230","publisher":"ARUP Laboratories"},{"title":"Identification and characterization of critical values in therapeutic drug monitoring: a retrospective analysis","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC11106295/","publisher":"Scientific Reports","year":2024},{"title":"Unveiling the recent trends: Therapeutic drug monitoring of antiepileptic drugs in Western India's Tertiary Care Hospital","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC12591522/","publisher":"Perspectives in Clinical Research","year":2025}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"Measures phenobarbital, a long-acting seizure medicine, in your blood. It helps your team see whether your dose gives a steady level in the usual range.","url":"https://bloodtesttracker.com/markers/phenobarbital","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}