{"id":"diphtheria-igg","name":"Diphtheria antitoxoid IgG","shortName":"Diphtheria IgG","aliases":["Diphtheria Antibody","Diphtheria Toxoid IgG","Diphtheria Immunity","Diphtheria Antitoxoid","Diphtheria Antibody, IgG","Diphtheria Antitoxin","Corynebacterium diphtheriae Antitoxin","Anti-Diphtheria Toxoid IgG","Diphtheria Toxoid Ab IgG","Diphtheria Toxoid IgG Antibody","Diphtheria Antitoxoid IgG","Diphtheria Vaccine Response","Anti Diphtheria"],"abbreviations":["Diphtheria IgG","Anti-DT IgG"],"loinc":[{"code":"13227-4","primary":true},{"code":"58787-3","primary":false},{"code":"5115-1","primary":false},{"code":"49189-4","primary":false}],"specimen":"serum","units":[{"ucum":"[IU]/mL","display":"IU/mL"},{"ucum":"m[IU]/mL","display":"mIU/mL"}],"referenceRanges":[{"population":"Adults","low":0.1,"high":null,"unit":"[IU]/mL","unitDisplay":"IU/mL","note":"This is a protective-level cutoff, not the central 95% of a healthy population. Quest reports 0.10 IU/mL or higher as protective. ARUP says a concentration above 0.1 IU/mL is usually considered protective. Some serosurveys also use 0.01 IU/mL (basic protection) and 1.0 IU/mL (long-term protection).","sources":[{"title":"Diphtheria Antitoxoid (test code 4865)","url":"https://testdirectory.questdiagnostics.com/test/test-detail/4865/diphtheria-antitoxoid?cc=MASTER","publisher":"Quest Diagnostics"},{"title":"Diphtheria Antibody, IgG (test 0050210)","url":"https://ltd.aruplab.com/Tests/Pub/0050210","publisher":"ARUP Laboratories"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"Measures antibodies against the diphtheria toxin to show whether vaccination or past exposure still gives you protection.","url":"https://bloodtesttracker.com/markers/diphtheria-igg","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}