We provide independent medical opinions for Veterans and federal employees who need clear, evidence-based medical documentation. Our work is grounded in accepted medical standards, careful record review, and professional judgment - never templates or predetermined conclusions.
Our focus is on medical clarity.
Nexus letters and medical opinions are written by licensed MD physicians with formal training in internal medicine, occupational & environmental medicine, addiction medicine, preventive medicine, and public health. In addition, our physicians have decades of experience diagnosing and managing primary care conditions. This background allows us to evaluate complex medical conditions, long-term health effects, and occupational or environmental exposures that may not be fully addressed in routine clinical care.
Each case is reviewed individually. If the available medical evidence does not support a medically defensible opinion, we will explain that clearly and may decline to issue a letter.
A credible medical opinion must be objective. We do not act as advocates, and we do not guarantee outcomes. Our role is to:
This independence protects the integrity of the opinion and ensures that it can withstand professional and administrative scrutiny.
Our physicians commonly evaluate conditions involving:
Each request is assessed on its own medical merits.
In addition to VA nexus letters, we provide medical opinions supporting federal disability accommodation requests. These opinions focus on functional limitations, medical necessity, and the relationship between a medical condition and workplace requirements.
As with all our work, these opinions are independent and evidence-based.
When you work with us, you can expect:
We believe clarity and honesty serve Veterans and agencies better than promises or guarantees.
The process begins with an intake form and submission of relevant records. We review each request to determine whether a medically supportable opinion can be offered before proceeding.

Dr. David received her medical degree from The Ohio State University College of Medicine and Public Health. After completing three years of residency in Internal Medicine, she relocated to Florida where she completed an additional two years of advanced subspecialty training in Occupational & Environmental Medicine, which included disabili
Dr. David received her medical degree from The Ohio State University College of Medicine and Public Health. After completing three years of residency in Internal Medicine, she relocated to Florida where she completed an additional two years of advanced subspecialty training in Occupational & Environmental Medicine, which included disability evaluations, independent medical examinations, and toxicology reviews. During that time, she simultaneously obtained a master's degree in public health, with concentration on environmental and occupational health. She achieved board certification in occupational medicine in 2001 and 2011.
Over the last thirty years, Dr. David has worked in a variety of clinical environments including university hospitals, HMOs, large hospital systems, military clinics, VA hospitals, nursing homes, and outpatient clinics, and her own private practice. She has also served as Associate Medical Director, Chief Quality Officer, and Patient Safety Director for state agencies responsible for healthcare administration and quality oversight. She has been providing independent medical opinions since 1997 and is an experienced writer of formal medical reports.
Dr. David is the founder and managing director of David Medical Services, a physician practice dedicated to improving health and quality of care.

Dr. Herrington received his medical degree from the University of Virginia. He is residency trained in General Surgery and General Preventive Medicine/Public Health, and additionally obtained a master's degree in public health. He is dual board certified in Public Health/General Preventive Medicine and Addiction Medicine. Dr. Herrington
Dr. Herrington received his medical degree from the University of Virginia. He is residency trained in General Surgery and General Preventive Medicine/Public Health, and additionally obtained a master's degree in public health. He is dual board certified in Public Health/General Preventive Medicine and Addiction Medicine. Dr. Herrington's work experience has included VA hospitals, occupational medicine clinics, primary care clinics, urgent care centers, and correctional medicine clinics. He has also served as Medical Director for correctional agencies in Maine, Vermont, Ohio, and Washington. He is an experienced writer of medical reports and has been providing independent medical opinions since 2001.
Dr. Herrington is a physician consultant at David Medical Services and provides litigation support for correctional healthcare cases.
A VA nexus letter is a formal medical nexus opinion that must withstand review by VA adjudicators. That requires careful analysis, medical expertise, and clear documentation.
Our approach differs from many nexus letter services because we focus on evidence-based medical reasoning, not shortcuts. So what sets our nexus letters apart?
We review the veteran's relevant medical records and service history to ensure the opinion reflects the individual facts of the case - not assumptions or generic templates.
For claims involving secondary service connection, toxic exposures, delayed-onset conditions, or disease progression, we incorporate current peer-reviewed medical literature to explain biological plausibility and timelines.
Each nexus letter explains how and why a condition may be related to military service or an already service-connected condition, using accepted medical principles and VA-recognized standards.
Our physicians provide independent medical opinions based on evidence and professional judgment. We do not guarantee VA outcomes and do not write advocacy letters.
Each nexus letter addresses one claimed condition, allowing adequate depth, clarity, and medical rigor.
Important Notice
David Medical Services (DMS) Nexus Letter Services do not establish a physician–patient relationship.
Our physicians provide independent medical opinions based on a review of records and relevant medical evidence, limited to addressing whether a Veteran’s claimed condition is objectively related to events, exposures, or circumstances that occurred during military service.
Any nexus letter, records review, or physician conference provided through this service is for medical opinion purposes only and should not be used for diagnosis, treatment, or medical decision-making. If you are seeking personal medical care or treatment recommendations, please consult your own licensed healthcare provider.
For nexus letter or accommodation requests, please use the appropriate intake form. This allows us to review your request efficiently and accurately.
You may also complete the web form on the left, or call / email our office if you prefer. Due to the medical-legal nature of our work, we are unable to provide claim advice or case assessments by phone or email.
215 Legion Way Southwest, Olympia, Washington 98501, United States
Open today | 10:00 am – 06:00 pm |
All hours are Pacific Time.
For emergencies, please call 9-1-1.