Client Services

Diego Contreras

Client Services Representative

Diego Contreras is a Client Service Representative at Whitman-Walker Health and has been in this role since 2012. He checks patients in for their appointments, schedules their appointments, and communicates messages from the patients to the medical providers. Prior to joining Whitman-Walker, Contreras provided assistance for after-school programs with the Mental Health Association of Montgomery County, Maryland. He has also volunteered with the Unitarian Universalist Congregation of Rockville, Maryland to plan the first LGBT-themed booth in Rockville’s Hometown Holidays.

Contreras received his bachelor’s degree in philosophy from the University of Maryland, College Park. He is bilingual in English and Spanish.

Dwaine Gasser

Senior Director of Clinical Infrastructure


Dwaine Gasser has been a Whitman-Walker staff member since 2005 in various administrative capacities. He currently serves as the Senior Director of Clinical Infrastructure and has responsibility for medical service operations and infrastructure. This includes responsibility for provider scheduling, front office operations (including call center), medical supplies, medical equipment, patient portal management, and pharmacy and lab oversight. From 2003 to 2005, Gasser worked at the Hospital for Sick Children, an inpatient rehabilitation hospital, and at Health Services for Children with Special Needs, which manages care and coordinates benefits for special needs children and adolescents in Washington, DC. From 1984 to 2003, he worked at Columbia Hospital for Women in Washington, DC, holding several positions, including vice president for professional services and vice president for support services. He was responsible for medical office practices, professional and support services departments, and more than 200 employees. His areas of expertise include budgeting, planning, credentialing, development and administration of policies and procedures, contracting, physician relations, business development, JCAHO accreditation, and federal and state inspections.

A native of Washington, DC, Gasser holds a bachelor’s degree in microbiology from the University of Maryland and a master’s degree in health services administration from the George Washington University.

Oneeka Hamilton

Senior Manager of Client Services

Oneeka Hamilton started at Whitman-Walker in January as the Senior Manager of Client Services. She obtained a bachelor’s degree in health promotions management from York College in New York and is currently pursuing dual Master’s degrees in healthcare administration and business administration. Hamilton lives in Gaithersburg, MD and considers herself a die-hard foodie. She has worked in health care over ten years and is most excited about working with the patients and staff. Hamilton’s office is located on the ground floor in ETMC.

Ted Hobart

Client Services Representative

Ted Hobart serves as a Client Services Representative, where he checks patients in, schedules their appointments, and communicates messages from the patients to the medical providers. Hobart began his work with Whitman-Walker in 2006 as an AIDS Walk Administrative Temp and later in 2007 became a full time employee as the AIDS Walk Outreach Coordinator and Race Director. From 2012 to 2014, Hobart served as the Events and Corporate Fundraising Coordinator and later served as the Stewardship Coordinator. Before joining Whitman-Walker, Hobart worked as a chef at various local and national high-end restaurants.

Hobart received his bachelor’s degree in anthropology with a minor in philosophy from Warren Wilson College. He also has an associate arts degree in Natural Resource Management from Sterling College and certificate in holistic nutrition and culinary arts from the Natural Gourmet Cookery School.

Iris Sanchez

Call Center Manager

Iris Sanchez is the Call Center Manager and former Client Services Representative at Whitman-Walker Health. Prior to joining, she worked at Children’s Hospital after relocating from Kansas, where she was stationed while in the U.S. Army as a Water Treatment and Medical Logistics Specialist.

Sanchez graduated from Friends University with an associate’s degree in general studies. She is a Notary of the State of Virginia and is bilingual in English and Spanish.

Otis “Buddy” Sutson

Client Services Representative

Otis “Buddy” Sutson is a Client Services Representative at Whitman-Walker. After twenty-five years of service with the Federal Government and the Air Force, he decided to take early retirement to embark on second career in the non-profit arena. Prior to coming to Whitman-Walker, Sutson served as a director at Damien Ministries and as a client services manager with Northern Virginia AIDS Ministry (NOVAM).  He has also served as chair with the Covenant Baptists Church AIDS Ministry and as a member of the Max Robinson Advisory Board.

Buddy is a native Washingtonian and enjoys city life. He holds an Associate’s Degree from Prince Georges Community College.

Sheila Walker

Client Services Representative

Sheila Walker is a Client Service Representative and Medical Records Clerk at our Max Robinson Center site. Sheila has served in these capacities for the past ten years.

Before coming to Whitman-Walker Health, Walker served as an Administrative Assistant and part-time teacher at the Covenant Early Childhood Development Center in Washington, D.C. and as a Substitute Teacher at Capitol Heights Elementary School in Capitol Heights, Maryland.