Patient Reviews

We understand that finding a provider that will truly listen to your concerns isn’t always easy. At Adult Gastroenterology Associates, our patients are our top priority. We strive to create a thoughtful and compassionate environment where you can trust that your care is customized to your needs. Take some time to browse through our reviews below, so you can read first-hand about the dedication and care that our specialists provide patients in the Tulsa, OK community.

5.0 Review from G.B. Source: Google Jul 07 2023

"I was notified by email that I needed to schedule my colonoscopy. I called for an appointment with Dr. Stanton and received all the information I needed when we met. My colonoscopy is scheduled later this month. As always, I felt well informed and totally at ease."

5.0 Review from D.H. Source: Google Jun 15 2023

"My visit to OSH was fantastic outside of the fact that I was there for a colonoscopy. That drink is disgusting and made me really nauseous. But all of the staff were amazing and really sweet. The only person who didn't even say hello or anything was one of the people in the or. He had lots of tattoos and facial piercings. I really wanted to see them too! But he wouldn't even look my way. It was kind of disappointing. But I know everyone has a bad day every now and then. So I don't think he deserves to get in trouble. He was never rude or anything. Just maybe a suggestion to smile and be friendly."

5.0 Review from D.M. Source: Google May 26 2023

"This is Joyce McCoy I have been a patient of Dr Nightingale for over 18 years.. he is the BEST ! I have PBC and he takes care of me 100% I do all my endoscopy and colonoscopy there at his office on Kelly Dr. In Tulsa"

5.0 Review from K.C. Source: Google May 25 2023

"Dr. Conkling is very personable and answers any & all questions without rushing through your consultation or making you feel uneasy about your upcoming colonoscopy. I highly recommend him & his entire office staff."

5.0 Review from K.D. Source: Google May 23 2023

"I was so impressed with their whole team. This was by far the BEST experience I have ever had in a Dr office/Procedure, by far! They had it together from start to end! Highly Highly recommend this practice! It can be nerve racking getting procedures done, they all were so friendly, caring, they checked on my several times, they are literally the Best! They even texted afterwards to make sure I was doing good not having any issues! They run a tight ship! Thank you so much for making my first colonoscopy an amazing experience. I am recommending EVERYONE to your office. What an amazing team you have, from checking in to being wheeled out! So friendly and kind I cannot say enough, highly impressed! Thank you so much ❤️"

5.0 Review from D.S. Source: Google Mar 25 2023

"Dr. Blonsky performed my colonoscopy with removal of benign polyps without incident. He explained everything in detail. The staff at Bailey owasso and anesthesiology done a great job also."

5.0 Review from T.R. Source: Google Jan 25 2023

"Recently got colonoscopy with Dr Nightengale. Very nice overall experience. A special shout out to Gentry, who made me feel like a VIP with her welcoming smile and courteous demeanor. Gentry and the other staff made a potentially worrisome experience much more pleasant through their courteous and professional behavior."

5.0 Review from H.I. Source: Google Jan 25 2023

"Friendly staff, knowledgeable. Now let’s hope they can schedule a colonoscopy in a descent amount of time. Since I’m on a waiting list, who knows?!!"

5.0 Review from D.W. Source: Google Dec 25 2022

"Several years ago I met him under duress with something stuck in my throat he performed the EGD with no trouble since. Has also done a colonoscopy in the past. He's a professional I will continue to be under his care."

5.0 Review from B.S. Source: Google Dec 25 2022

"Absolutely a wonderful experience. This was the first time I met Dr. Nightengale for my first colonoscopy potential need. I felt like he had been my physician for years. He made me feel completely comfortable and answered all my questions respectfully and thoroughly."

5.0 Review from J.C. Source: Google Nov 25 2022

"Dr. Nightengale has been my gastroenterologist for over 20 years. In my opinion he is as knowledgeable in his field as any person could be. He is very efficient in his consultations with you. No questions left unanswered. I have had multiple EGD’s as well as colonoscopies and his review of the results is always very thorough. I highly recommend Dr. Nightengale."

5.0 Review from S.A. Source: Google Nov 25 2022

"I have known Dr Mark Nightengale for years, have trusted his colonoscopy experience and will continue to reschedule whenever he recommends. A great friend as well."

5.0 Review from K.S. Source: Google Nov 25 2022

"I have seen him twice for a routine colonoscopy. I have also had hemi-bands. He is always nice and explains the procedure. He follows up with you to make sure there are no questions are concerns. I would recommend him to family and friends."

5.0 Review from J.P. Source: Google Nov 25 2022

"First appointment with a gastroenterologist discussing getting scheduled for a colonoscopy. Friendly staff and doctor. Very professional and prompt."

5.0 Review from D.W. Source: Google Oct 25 2022

"Dr. Nightingdale's staff is Tulsa's best in colonoscopy's in my opinion. His staff has preformed my last 4 colonoscopys. Each time his staff was always very professional and courteous. I was in and out in under 1 hour. I will go back to him for my next one as well! I can't say enough Great surgeon Great Staff!!!"

5.0 Review from C.B. Source: Google Oct 25 2022

"Once again, I had the best experience I could hope for at my recent colonoscopy with Dr. Christian Clark at the Tulsa Endoscopy Clinic. He is open to all questions and answers them fully. The entire staff is dedicated to making patients feel comfortable from the moment they check in."

5.0 Review from S.P. Source: Google Oct 25 2022

"I went in for my colonoscopy and was greeted by a friendly staff right from the beginning. My procedure was flawless. I didn't notice any issues whatsoever, woke up to a friendly voice and on my way I was! Highly recommended Dr Blankenship and his great staff!"

5.0 Review from P.U. Source: Google Aug 25 2022

"I was pleased with the services that I received from Dr. Nightengale and staff for my colonoscopy/endoscopy procedure."

5.0 Review from L.R. Source: Google Jul 25 2022

"Dr. Conkling was professional and thorough in my care before, during, and after my colonoscopy. He called me personally with the results and patiently answered all questions. I highly recommend him."

5.0 Review from J.W. Source: Google Jul 25 2022

"Dr Blankenship and his staff are always great! Just had my second colonoscopy with him and I would recommend him 100%"

5.0 Review from V.G. Source: Google Jun 25 2022

"Egd and colonoscopy went just as planned and so far I haven't had a problem Staff was very nice. Awaiting biopsy results but they gave piece of minds that everything looked normal. Bowel prep was WAY easier with plenvu than what I have used before. Dr Blankenship was very nice! All staff involved were wonderful and they used propofol so I was OUT!! UNCONSCIOUS!"

5.0 Review from J.B. Source: Google May 25 2022

"Exceptional experience with Dr Patel and Adult Gastroenterology Associates. They provided a prescription to prepare my GI tract for the colonoscopy which was much more pleasant than previous experiences. Arrived on-time at 10:15am and the office processed the paperwork quickly. Both Dr Patel and the nurse anesthetist visited with me beforehand, kindly responding to my questions by 10:45am. Procedure was over in 45 minutes and I was alert enough to get dressed and my wife picked me up at 11:45am. Before I left, the report was on the patient portal and biopsy report was available the following afternoon. Once again, an exceptional experience!"

5.0 Review from A.T. Source: Google May 25 2022

"I recently had a colonoscopy and an upper GI which Dr Markham Nightengale performed. I was totally happy with his services and my care from his staff. I was complete informed on how to take my prep and how it would work. I arrived on time the next morning and filled out my papers I was taken back to get prepared and his staff was so nice and told me exactly what they were going and how it would go. When it was my turn and by the way it was on time I was taken back and they did the procedures and then off I went to recover. Everyone that I came in contact with was so nice and pleasant. For a procedure no one looks forward to it was no problem and Dr Nightengale came in before I left to let me know what he had done and that he had told my husband already. I was completely satisfied with my experience with him. Thank you Dr Nightengale"

5.0 Review from P.B. Source: Google May 25 2022

"Was very nervous. First time for Colonoscopy. Very professional. Made me feel very comfortable."

5.0 Review from L.L. Source: Google May 25 2022

"My visit was good I got in fast learned about early detection of colon cancer everybody should get a colonoscopy at age 45 and I went with extreme acid burning heartburn I learned I have GERD LisaLogan"

5.0 Review from S.W. Source: Google May 25 2022

"From the minute I walked in the office, I was welcomed by receptionist, very friendly and professional which put me at ease immediately. Everything was right on time and at one point I had at least 4 nurses check on me, each introduced themselves while being prepped for my colonoscopy. The Anesthesiologist came in and explained every step and then Dr. Stanton personally came in and walked me through every step and asked for any questions I may have. Just may be the best medical experience one could ask for considering why I was there! Everyone, including Dr. Stanton, were right there when I woke up and explained how the procedure went and what to expect the rest of the day. Honestly, I would recommend Dr. Stanton and entire Staff to anyone I know and encourage everyone at a certain age to get your colonoscopy here with NO WORRIES!! My Thanks to everyone in the office!! Shawn West"

5.0 Review from T.V. Source: Google May 25 2022

"I had a colonoscopy scheduled with Dr Clark. The receptionist, though very busy, was very pleasant. The nurses were very kind and attentive. Dr Clark himself was very straight forward about what to expect and let me know the risks. The procedure itself went as well as possible - they made sure I was out and I’ve had no issues afterwards. Would definitely recommend him to others!"

5.0 Review from S.C. Source: Google May 25 2022

""I want a colonoscopy" says no one! But, if you are in need of one, this is the place to go! Kind, personable, courteous staff. Easy prep. I would highly recommend them!"

5.0 Review from K.M. Source: Google May 25 2022

"I highly recommend Kevin McNamara. He has performed two procedures for my family over the last two years, most recently a colonoscopy for myself. While a colonoscopy is not a procedure that you typically look forward to, I was more relaxed and had no apprehensions with the procedure knowing that he was performing it. He is a caring, professional and thorough doctor."

5.0 Review from K.D. Source: Google May 25 2022

"Dr. McNamara and his staff made me feel comfortable with the process of a routine colonoscopy. They went above and beyond when I was nervous and had lots of questions. While no one can say they are looking forward to this procedure, I’d say this team at least makes it as easy and comfortable as possible."

5.0 Review from D.B. Source: Google May 25 2022

"Dr. McNamara was great. Very kind and informative. Explained everything prior and answered all of my questions.. So was everyone at Tulsa GI. The nurses there are one of a kind and so are the lady's at the front desk. This was my first colonoscopy and I am always nervous about procedures. They all went the extra mile to make me feel at ease. Highly recommend!"

5.0 Review from M.L. Source: Google May 25 2022

"Been going to Dr. Nightingale since I had my first colonoscopy 30 years ago. He is very friendly, direct, professional, concerned about you when speaking with you. He’s a great person. His staff is very helpful and professional. The center where the procedures take place is clean and comfortable. Both the Dr.’s office and the center are taking Covid precautions."

5.0 Review from G.N. Source: Google May 25 2022

"This was as good as it gets for a colonoscopy. Everyone was very cordial and professional. Had absolutely no complications from procedure. See you in five years!"

5.0 Review from S.C. Source: Google May 25 2022

"Very thorough by listening and asking questions to get the best diagnosis and care. He is friendly and personable. I was at ease when I left the office knowing the best way to take care of my problem is to have a colonoscopy/endoscopy to get a thorough diagnosis. I asked questions that he took the time to answer and explain his answers. I highly recommend Dr. Nightengale. He is an excellent gastroenterologist!"

5.0 Review from C.J. Source: Google May 25 2022

"If you have to have a colonoscopy this is the place to go, they are so nice. They make everything as comfortable as possible. They stay on schedule . Dr. Nightingale has a good bedside manner"

5.0 Review from B.D. Source: Google May 25 2022

"Just completed 3rd colonoscopy procedure done by Dr. Nightengale. He spoke with me prior to the procedure in his usual pleasant manner. A detailed report including photos was provided afterwards. Checking in at the lobby was efficient. Initial prep by nurse and anesthesiologist went smoothly. Checkout also. All staff from checkin to checkout were pleasant."

5.0 Review from A.A. Source: Google May 25 2022

"If there is such a thing as a great experience w/having a colonoscopy-this was it! Extremely nice staff from front office through the nursing staff! Highly recommend this place"

5.0 Review from O. Source: Google May 25 2022

"New patient in for colonoscopy screening due to family history. Dr. Volak's knowledge and skill are accompanied with an easiness, dry sense of humor, and genuineness. Dr. Volak clearly explained every step of the prep and the procedure, including what to expect, ensured that I understood, and answered questions I had with an interest in educating me. Dr. Volak used the most up to date technology, including a more than tolerable prep, to ensure he was able to get a clear and thorough view of my colon while decreasing the uncomfortableness patients typically experience. I need repeats every five years and Dr. Volak is my choice to handle all my future gastroenterology care."

4.0 Review from K.V. Source: Google May 25 2022

"Dr Blankenship is a great Doctor but the staff is lacking . The receptionist and nursing staff never returned my calls nor did they ever tell me the results of my colonoscopy. I have called and called but no one will call me back. I scheduled an appointment but never got a confirmation nor a reminder so I missed my appointment. I cannot get any communication at all."

5.0 Review from M.A. Source: Google May 25 2021

"Dr. Volack is an amazing Gastroenterology Specialist, probably the best in Tulsa, as a retired RN, I've worked with and seen several, personally and professionally. He is engaging, never rushes through details of findings and takes the time to explain things in layman's terms. I will forever be indebted to him for finding my cancerous 24mm polyp September 4th, 2018. He has been a part of my treatment plan since that time, though I chose not to have Chemotherapy, BUT instead, chose Naturopath and he respected my decision. I am cancer free today, having had a Colonoscopy yesterday, and for the first time since I started having Colonoscopies, there were NO polyps. If you're looking for an amazing Gastroenterology Specialist, look no further than this gifted Physician."

5.0 Review from L.R. Source: Google May 25 2021

"Great experience! I was completely comfortable during my entire colonoscopy procedure from start to finish! I felt heard and taken care of!"

5.0 Review from R.W. Source: Google May 25 2021

"From the moment I walked in, I was treated Like I was family. The Receptionist, the Nurse, and Dr. Blankenship was exceptionally well Concerned about the pain I was in. And Decided from from my CT. SCAN THAT I NEEDED A NEUROLOGIST TO CORRECT THIS PAIN I WAS HAVING. I'VE BEEN A PATIENT OF HIS BEFORE. FOR COLONOSCOPY."

5.0 Review from J.R. Source: Google May 25 2020

"NO ONE wants to go through the prep for a colonoscopy, but if you have to, Dr. Blankenship and his staff at Tulsa Endoscopy Center is the one to see. The nurses and front office staff are the loveliest group of women I have ever come into contact with in a medical facility, and they make an otherwise uncomfortable situation so pleasant; Dusty, the Anesthesiologist is so comforting and nice, and Dr. Blankenship is the best! Thank you thank you to them for treating me with kid-glove hands!"

5.0 Review from S. Source: Google May 25 2020

"The best recommendation I can offer is that I've used Dr. Volak's services for colonoscopy before. Obviously, not the most joyously-anticipated procedure, Dr. Volak and his associates make the experience as comfortable and professional as can possibly be expected. The whole procedure from originating consultation through completion (in my case, biopsy of a polyp) were done with confidence, discretion, and compassion. I'll be seeking Dr. Volak's services five years from now."

5.0 Review from M.D. Source: Google May 25 2019

"Listened to my concerns. He scheduled me right away for an EGD to address my concerns."

5.0 Review from L.H. Source: Google May 25 2019

"This was my first colonoscopy and I was nervous. Dr Stanton is so kind and professional. The nurses were all friendly and put me at ease. He also was nor rushed afterward while explaining my results. This procedure was quick and painless. It’s true what they say about the prep being the unpleasant part, although not as bad as I expected. Don’t put it off."

5.0 Review from R.M. Source: Google May 25 2019

"I was referred to Dr. Conkling by my primary physician. I appreciate the time he took to thoroughly discuss what had been going on with me health-wise these last 2 months and his thoughts on the matter. This is not something you get very often in the medical community. The endoscopy and colonoscopy he did for me went without a hitch and was professional, efficient and as much as it could be, stress-free. He explained my results thoroughly and in private with me and my spouse. Overall, my experience has been excellent with this doctor."

5.0 Review from L.M. Source: Google May 25 2018

"He is the kindest, nicest most compassionate doctor I have ever had. He has always put me at ease with all of my procedures and expains everything completely. I had put off having a colonoscopy and seriously it was a piece of cake. I am so glad he's my doctor..."

5.0 Review from R.C. Source: Google May 25 2018

"Dr. Kliewer has accomplished all four of the colonoscopy procedures I have had over the years and he still does an excellent job. He is extremely personable, and easy to converse with about the procedure. Great bedside manners and keeps the patient first and foremost in mind during the preop, actual operation, and post operation process. I highly recommend him and his staff."

5.0 Review from C.W. Source: Google May 25 2018

"Dr. Kliewer is an excellent doctor who has performed a Colonoscopy on me twice to remove polyps and insure my health. The office staff is great to work with and everything is done efficiently and well. At the end of each procedure, Dr. Kliewer sat with me for a consultation to show me pictures and review his findings and prognosis. Having had colon cancer in my family history, I continue to know that I am healthy, and if something were to appear, it would be caught early. I feel confident I am in good hands."