Home Page


Currently, Greenhouse is not offering the COVID-19 vaccine.  Larger health systems and pharmacies that have the space to meet the storage requirements of the vaccine and monitor patients after the vaccine is administered will be offering the vaccine. If you have received the vaccine, we recommend following the CDC’s guidelines for fully vaccinated people.


Caring for Someone at Home
City of Philadelphia COVID-19
Coronavirus Q and A

Information for Travelers
Testing Sites
Vaccine Card Dos and Don’ts
What to Do if You are SickWhat You Need to Know About Variants

If you have traveled, or plan to travel, to an area where there are high amounts of COVID-19 cases, it is recommended that you stay at home for 14 days upon return to Pennsylvania.  Greenhouse Internists requires that you wait at least 14 days upon your return to PA before you can visit the office.  If you need to speak to a provider sooner for a health concern, you would need to schedule a telehealth appointment.   For the latest travel guidance, click here.


Flu shots are available by appointment on Wednesday and Friday afternoons, starting 9/1/21.   Please call the office or use the patient portal to request your flu shot. Keep in mind, we get our flu shots through Vaxcare, a third party vendor. Some insurance plans, such as Amerihealth, Health Partners, and Keystone First, are not in network with Vaxcare.  Before we schedule your appointment, we will verify that your insurance is in network with Vaxcare.  If you are not eligible through Vaxcare, you will need to get your flu shot at a local pharmacy and they will send us an update.

Since the beginning of the COVID-19  pandemic, Greenhouse Internists has strived to keep our patients and employees safe by implementing numerous safety measures, such as allowing more time between patient visits to ensure social distancing and time for disinfecting exam rooms, screening all patients before entering the office, offering and telehealth appointments, and requiring an appointment to enter the office.   (To review all COVID-19 – related office information and policies, click here).


1.  We are offering more more telehealth appointments (phone or video) as needed to maintain social distancing in the office.

2.  We screen all patients prior to in-person appointments per state and local guidance. We ask that all patients/visitors are patient during the screening process and answer each question thoughtfully and thoroughly.

3.  All patients who visit the office without an appointment will be told that they must call the office to discuss their concern. No concerns will be addressed at the door.


Masks must be worn the entire time you are in the office.  If you don’t think you will be able to wear a mask correctly (covering your nose and mouth) the entire time you are in the office, then you should schedule a telehealth visit instead.

Thank you for your cooperation.  Please stay safe and healthy.

Elizabeth Fabens

Dr. Elizabeth Fabens grew up in Ohio and went to college at Brown University, graduating in 1976. She worked in the health care field for several years and then started medical school at the University of Massachusetts Medical School in Worcester, Mass in 1981. She moved to Philadelphia in 1985 to start her residency in Internal Medicine at The Medical College of Pennsylvania Hospital. After residency, she worked for several years at one of the city health centers in Germantown.
Dr. Fabens previously worked as a medical consultant at the Abbottsford Health Center and has also worked at the Medical College of Pennsylvania AIDS Clinic.
Dr. Fabens has been at Greenhouse Internists since June, 1990.She is Board Certified in Internal Medicine and has an additional qualifying certificate in Geriatrics. 

Dan Peterson

Dr. Daniel Peterson graduated from Bucknell University and Penn State University School of Medicine. He completed his internship at Mary Imogene Bassett Hospital in Cooperstown, New York, and his residency at St. Luke’s-Roosevelt Hospital Center in Manhattan.
He remained at St. Luke’s-Roosevelt as teaching faculty and in a part-time private practice. He directed the resident curriculum in Evidence Based Medicine and was the director for the institution’s participation in the Academic Chronic Care Collaborative.
 Dr. Peterson is Board Certified in Internal Medicine. He enjoys riding his bike on the Wissahickon trails, reading biographies, and spending time with his family.

Tryphena Hsi, CRNP, joined Greenhouse in March 2020.  She has worked as a Nurse Practitioner for over 7 years and has much experience in primary care and women’s health.  Most recently she practiced at Covenant House Health Services, where she provided primary care services to adult and geriatric patients with multiple chronic illnesses. Tryphena is passionate about patient education and empowering patients to make positive health changes. Tryphena is available to see patients for urgent and follow up needs in the office or by virtual visit.

Diane Fox, CRNP, joins us with over 20 years as a Nurse Practitioner, with most of her experience in primary care.  She has her nursing degrees from La Salle and Penn State Universities. Most recently, she provided primary care to residents of Abramson Senior Care, managing acute and chronic conditions, as well as palliative and hospice care.  Diane is especially interested in geriatrics, palliative and advance care planning, and educating patients to help them make positive health behavior changes.  Outside of work, Diane enjoys lacrosse, baking, and spending time with her family and friends.