{"id":"nrbc-percent","name":"Nucleated Red Blood Cells (nRBC) (Percent)","shortName":"nRBC %","aliases":["NRBC","NRBC %","Nucleated Red Blood Cells","Nucleated RBC","NRBC/100 WBC","Nucleated Erythrocytes","NRBC Percent","Nucleated RBC (percent)","Nucleated Red Blood Cells %","Nucleated Red Blood Cells (%)","NRBC (%)","nRBC","nRBC %","Nucleated RBC %","NRBC per 100 WBC","Nucleated RBC per 100 WBC"],"abbreviations":["NRBC","nRBC","NRBC%"],"loinc":[{"code":"58413-6","primary":true},{"code":"19048-8","primary":false},{"code":"18309-5","primary":false}],"specimen":"whole-blood","units":[{"ucum":"%","display":"% (per 100 WBC)"},{"ucum":"/100{WBC}","display":"/100 WBC"}],"referenceRanges":[{"population":"0.011+","low":null,"high":0,"unit":"%","unitDisplay":"% (per 100 WBC)","note":"Healthy people are expected to have none, so any result above 0 is usually flagged. ARUP lists 0% for ages 4 days and older (0.011 years is about 4 days), and Labcorp lists 0 to 0 above 30 days and prints 'Not Estab.' before that. OHSU allows up to 0.3 per 100 white cells at all ages. Counts are per 100 white blood cells, even when the report shows a % sign.","sources":[{"title":"CBC with Platelet Count and Automated Differential (test 0040003), hotline effective March 1, 2021","url":"https://ltd.aruplab.com/api/ltd/hotline/0040003/44232","publisher":"ARUP Laboratories","year":2021},{"title":"Pediatric Testing Reference Ranges","url":"https://www.labcorp.com/content/dam/labcorp/drupal/178250_DX_TL_PediatricTestRef_Final.pdf","publisher":"Labcorp"},{"title":"CBC with Differential","url":"https://www.ohsu.edu/lab-services/cbc-differential","publisher":"Oregon Health & Science University (OHSU Lab Services)"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"How many nucleated red blood cells are in the blood for every 100 white blood cells. Healthy people usually have none after the first weeks of life.","url":"https://bloodtesttracker.com/markers/nrbc-percent","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}