Our Story

At Quotient Health, we believe great medicine starts with knowing you, not just your symptoms, but your complete health story.

Take Charge of Your Health

We go beyond traditional primary care with longevity as our mission.

Clarity Starts Here.

Dr. Justin Greiwe, MD

Dr. Ryan Collar, MD, MBA

Our Team of Experts
Dr. Justin Greiwe, MD

Dr. Justin Greiwe, MD

Co-Founder & Head of Longevity Medicine

An immunologist and longevity specialist dedicated to advancing proactive, data-driven care.

Renowned for his work with the Cleveland Clinic and Bernstein Allergy Group.

Dr. Ryan Collar, MD, MBA

Co-Founder & CEO

A distinguished plastic surgeon, healthcare innovator, and entrepreneur.

Previously Co-Founder & CSO at Invisible Ink (now Removery).

Dr. Katie Sheridan, MD, MSCP

Dr. Katie Sheridan, MD, MSCP

Head of Primary Care & Menopause Specialist
Family medicine physician committed to personalized, prevention-focused care. Expert in menopause and midlife hormonal health.

With a distinguished background at The Ohio State University College of Medicine and TriHealth.

John Zerbe, MD

John Zerbe, MD

Internal Medicine & Primary Care

Board-certified internal medicine physician dedicated to optimizing wellness.

Former Global Medical Director at GE Aviation, CEO of The Zerbe Wellness Center, and former team physician for the Cincinnati Reds and Cincinnati Bengals.

Jack McDonnell, MD, MS

Immunologist
& Data Scientist

Expert in translating complex health data into actionable insights.

Having held key positions at Cleveland Clinic and Case Western Reserve University.

Jason Harbin

Jason Harbin

Head of Fitness & Wellness

Health & performance coach known for results-driven, data-informed programs.

Extensive experience as a personal trainer, coach, and fitness expert.

Kari Butcher, RN

Kari Butcher, RN

Registered Nurse

Experience in inpatient hospital care and perioperative services, with a focus on patient support and care coordination.

Provides attentive, individualized care and helps patients stay engaged throughout their health journey.

Stephanie Shoemaker, RN

Stephanie Shoemaker, RN

Registered Nurse

Background in surgical and procedural care across operating room, pre-operative, post-operative, and in-clinic settings.

Focused on longevity and helping patients take a proactive approach to their health.

Mary Ross Freeman, DNP, PMHNP-BC

Mary Ross Freeman, DNP, PMHNP-BC

Psychiatric Mental Health
Nurse Practitioner

Specializes in mental health, resilience, and the role of psychological well-being in long-term health.

Trained at Rush University with clinical experience at the Road Home Program.

Lauren Dorcheff, RN

Registered Nurse

Background in Family Medicine with a focus on prevention and patient education.

Works closely with patients to build understanding and support long-term health decisions.

April Collar

April Collar

Director of Patient Experience

Leads the design and delivery of the Quotient Health patient experience, overseeing environment, touchpoints, and brand expression.

Background in design, content, and hospitality, with a focus on creating a refined, intentional, and cohesive care journey.

Quotient Cares

Quotient Health champions our community by partnering with local artists, chefs, and creators to elevate wellness through connection and culture.