A photo of Omar Niss.

Omar Niss, MD

  • Member, Division of Hematology
  • Director, Classical Hematology
  • Associate Professor, UC Department of Pediatrics


MD: Jordan University of Science and Technology, 2004.

Residency: Pediatrics, University of Nebraska Medical Center, Omaha, NE, 2010.

Fellowship: Pediatric Hematology Oncology, Cincinnati Children’s Hospital Medical Center, 2013; Sickle Cell Scholar, Cincinnati Children’s Hospital Medical Center, 2014.

Certification: Pediatrics, 2010; Pediatric Hematology/Oncology, 2015.


Pediatric hematology; sickle cell disease; hemoglobinopathies; congenital anemias; immune mediated cytopenia

Services and Specialties

Cancer and Blood Diseases, Sickle Cell and Hemoglobin Disorders, Cardio-Oncology


Cardiopulmonary complications of sickle cell disease; congenital anemias

Research Areas


Additional Languages

Arabic, French

Insurance Information

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Improving Transition of Emerging Adults with Sickle Cell Disease to Adult Care through a Multidisciplinary Process: The Development of a Transition Clinic to Support Transition Success. Fenchel, L; Jackson, F; Walker, B; Manuel, C; Hooks, D; Allen, T; Thant, MM; Karkoska, K; Smart, LR; Joffe, NE; et al. Blood. 2023; 142:5055.

Genetic Variants in Canonical Wnt Signaling Pathway Associated with Pediatric ITP. Kim, TO; Geris, JM; Grimes, AB; Grace, RF; Lambert, MP; Rose, MJ; Shimano, KA; Niss, O; Neunert, C; Nakano, TA; et al. Blood. 2023; 142:2593.

Congenital Dyserythropoietic Anemia Type II: An Update from the Congenital Dyseryhtropoietic Anemia Registry of North America (CDAR). Elgammal, Y; Risinger, M; Husami, A; Walden, J; Gupta, S; Shah, NC; Boyer, J; Abajas, YL; Winstead, M; Miller, DW; et al. Blood. 2023; 142:1079.

Individualized, PK-Guided Dosing of Hydroxyurea Is Not Associated with Increased Hematologic Toxicity Compared to Weight-Based Initial Dosing: Interim Results from the Hops Trial. Appiah-Kubi, A; Jacob, SA; Heeney, MM; Brown, C; Creary, SE; Hollenkamp, CR; Meier, ER; Niss, O; Piccone, CM; Quarmyne, M; et al. Blood. 2022; 140:5416-5417.

Early hydroxyurea use is neuroprotective in children with sickle cell anemia. Karkoska, K; Pfeiffer, A; Beebe, DW; Quinn, CT; Niss, O; McGann, PT. American Journal of Hematology. 2022; 97:E368-E370.

Chapter 3 Classification and diagnosis of anemia in children and neonates. Niss, O; Quinn, CT. Lanzkowsky's Manual of Pediatric Hematology and Oncology. : Elsevier; Elsevier; 2022.

Rapid and automated quantitation of dense red blood cells: A robust biomarker of hydroxyurea treatment response. Sadaf, A; Quinn, CT; Korpik, JB; Pfeiffer, A; Reynaud, M; Niss, O; Malik, P; Ware, RE; Kalfa, TA; McGann, PT. Blood Cells, Molecules, and Diseases. 2021; 90:102576.

Early initiation of hydroxyurea (hydroxycarbamide) using individualised, pharmacokinetics-guided dosing can produce sustained and nearly pancellular expression of fetal haemoglobin in children with sickle cell anaemia. Quinn, CT; Niss, O; Dong, M; Pfeiffer, A; Korpik, J; Reynaud, M; Bonar, H; Kalfa, TA; Smart, LR; Malik, P; et al. British Journal of Haematology. 2021; 194:617-625.

Implementation of near-universal hydroxyurea uptake among children with sickle cell anemia: A single-center experience. Karkoska, K; Todd, K; Niss, O; Clapp, K; Fenchel, L; Kalfa, TA; Malik, P; Quinn, CT; Ware, RE; McGann, PT. Pediatric Blood and Cancer. 2021; 68:e29008.

Hydroyxurea improves cerebral oxygen saturation in children with sickle cell anemia. Karkoska, K; Quinn, CT; Niss, O; Pfeiffer, A; Dong, M; Vinks, AA; McGann, PT. American Journal of Hematology. 2021; 96:538-544.

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