ERROL OLWYN GRANNUM MD
NPI 1508897935
Ophthalmology in Mcallen, TX

Q: What is Errol Grannum's NPI number?

The NPI number for Errol Grannum is 1508897935. It was assigned to this individual provider in the NPPES registry on July 5, 2006.

Q: What is Errol Grannum's specialty?

The primary specialty registered for this NPI is Ophthalmology with taxonomy code 207W00000X.

Q: When was this NPI record last updated?

The NPPES record for Errol Grannum was last updated on July 8, 2007. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 19 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.

Active since July 05, 2006PECOS EnrolledAccepts Medicare Assignment

0/100

CMS Quality Rating

1910 S 1ST ST, MCALLEN, TX 78503(956) 687-3937(956) 687-3938 Get Directions Write a Review

NPPES record last updated: July 8, 2007. Verified against the NPPES registry weekly; last sync: August 09, 2026.

On this page

About Errol Olwyn Grannum Md NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

ERROL OLWYN GRANNUM MD (NPI 1508897935) is an individual ophthalmology provider in Mcallen, Texas, licensed in Texas (K5972) and active in the NPI registry since July 2006. He is enrolled in Medicare PECOS, is affiliated with Rio Grande Regional Hospital, and is a graduate of Yale University School Of Medicine (1989).

NPPES Registry Identity

NPI1508897935

Entity TypeIndividualMale

Primary Taxonomy207W00000X

Provider Legal NameERROL OLWYN GRANNUMCredential: MD

Location Address1910 S 1ST STMcallen, TX 78503-1255

Mailing Address1910 S 1st StMcallen, TX 78503-1255 · (956) 687-3937 · Fax (956) 687-3938

Phone(956) 687-3937

Fax(956) 687-3938

Sole ProprietorYes

Medical School CMSYale University School Of MedicineGraduated 1989

Enumeration DateJuly 5, 2006

Last NPPES UpdateJuly 8, 2007

✔ NPI 1508897935 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyOphthalmologyAllopathic & Osteopathic Physicians

Taxonomy Code207W00000X

License✔ Licensed in TX · K5972

Definition

An ophthalmologist has the knowledge and professional skills needed to provide comprehensive eye and vision care. Ophthalmologists are medically trained to diagnose, monitor and medically or surgically treat all ocular and visual disorders. This includes problems affecting the eye and its component structures, the eyelids, the orbit and the visual pathways. In so doing, an ophthalmologist prescribes vision services, including glasses and contact lenses.

1910 S 1ST ST, Mcallen, TX 78503

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Other Identifiers 1

Medicare UPING61818TX

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Blue Cross and Blue Shield of Texas, Molina Healthcare, UnitedHealthcare.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Errol Olwyn Grannum Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID8022011915

PECOS Enrollment IDI20060815000073

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Areas of Expertise CMS Part B claims 12

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Established patient problem focused exam of visual system 92012

This is a routine check-up for existing patients focusing on the visual system. It involves examining your eyes to detect any potential issues or changes in your vision. It's a crucial part of maintaining good eye health.

610 services272 patients

Measurement of corneal pressure 92145

Measurement of corneal pressure, also known as tonometry, is a simple, painless procedure that checks the pressure inside your eye. It's important for detecting conditions like glaucoma. A device gently touches your eye to take the reading, which is usually quick and doesn't cause discomfort.

280 services175 patients

Exam of visual field with extended testing 92083

An extended visual field exam is a detailed test to evaluate your peripheral (side) vision. It helps to detect any potential blind spots which may not be noticeable in daily life. These could be caused by eye diseases like glaucoma, or neurological conditions.

160 services144 patients

Exam of the internal drainage system of eye 92020

This is a procedure where your doctor examines the eye's internal drainage system, essential for maintaining eye pressure. They use specialized tools to check for blockages or damage that might lead to conditions like glaucoma. It's non-invasive and painless.

123 services120 patients

Imaging of optic nerve 92133

Imaging of the optic nerve is a non-invasive procedure that captures detailed pictures of your optic nerve. It helps doctors assess eye health, particularly for conditions like glaucoma. It's painless, quick, and uses safe technology like MRI or OCT (Optical Coherence Tomography).

120 services118 patients

New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more 99204

This is a first-time office or outpatient visit lasting between 45-59 minutes. The healthcare provider evaluates your health, discusses your medical history, and may suggest further tests or treatments. It's an opportunity to ask questions and understand your health better.

69 services69 patients

Photography of the retina 92250

Photography of the retina, also known as retinal imaging, is a non-invasive procedure that captures images of the back of your eye. This helps doctors identify and monitor conditions like glaucoma, macular degeneration, or diabetic retinopathy. It's painless and quick, often part of a routine eye exam.

60 services57 patients

Creation of eye fluid drainage tracts in iris using a laser, per session 66761

This procedure uses a laser to create small drainage tracts in the iris, the colored part of your eye. This helps excess fluid escape, reducing pressure in the eye that can cause glaucoma. It's performed in sessions.

38 services24 patients

Laser repair to improve eye fluid flow 65855

Laser repair to improve eye fluid flow is a procedure aimed at treating glaucoma. A laser is used to create a small hole in the eye's drainage system, allowing fluid to flow out more easily. This helps to lower the pressure inside the eye, reducing the risk of vision loss.

30 services21 patients

Removal of eyelashes using forceps 67820

The removal of eyelashes using forceps is a simple procedure where a medical professional gently extracts unwanted or problematic eyelashes with a specialized tool. This is often done to alleviate discomfort or to treat conditions like trichiasis, where eyelashes grow inward.

25 services16 patients

Ultrasound scan of cornea to determine thickness 76514

An ultrasound scan of the cornea is a non-invasive procedure that uses sound waves to measure the thickness of your cornea. This helps in diagnosing certain eye conditions and planning treatments. No discomfort or pain is typically experienced.

19 services19 patients

Extended exam of the back part of the eye with retinal drawing 92201

This procedure involves a detailed examination of the back part of your eye, including the retina. It helps identify any abnormalities or issues. A retinal drawing is made to record findings. It's non-invasive and crucial for maintaining eye health.

12 services11 patients

Hospital Affiliations CMS Care Compare

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Rio Grande Regional Hospital

Acute Care Hospitals · Mcallen, TX

3/5 CMS rating

OwnershipProprietary

CMS Certification Number450711

Location101 E Ridge RdMcallen, TX 78503 · Hidalgo County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 78503 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient

$126.40 typical visit price

range $54.84 – $166.88

Typical copayment $31.60 (range $13.71 – $41.72)

Most-billed visit code 99204

Established Patient

$68.55 typical visit price

range $17.52 – $136.11

Typical copayment $17.13 (range $4.38 – $34.02)

Most-billed visit code 99213

Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

0/100

MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program

Individually scored

Quality

Improvement Activities

Other Providers at the Same Location NPPES 5

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

SOUTH TEXAS NEUROLOGICAL CENTER, P.A.

Psychiatry & Neurology (Neurology)

1910 S 1ST ST, SUITE 200
MCALLEN, TX 78503

Hidalgo County (956) 687-7885

ERROL O GRANNUM

Ophthalmology

1910 S 1ST ST, SUITE 400
MCALLEN, TX 78503

Hidalgo County (956) 687-3937

RUY MIRELES QUINTANILLA

Specialist

1910 S 1ST ST, STE 200
MCALLEN, TX 78503

Hidalgo County (956) 687-7885

DR. ROBERTO A ARGUELLO M.D.

Ophthalmology

1910 S 1ST ST, SUITE 100
MCALLEN, TX 78503

Hidalgo County (956) 687-8475

TEXAS BIONICS, INC

Prosthetic/Orthotic Supplier

1910 S 1ST ST, SUITE 500
MCALLEN, TX 78503

Hidalgo County (956) 994-9528

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Errol Grannum's NPI number?

The NPI number for Errol Grannum is 1508897935. It was assigned to this individual provider in the NPPES registry on July 5, 2006.

Where is Errol Grannum located?

Errol Grannum practices at 1910 S 1st St, Mcallen, TX 78503. The listed phone number is (956) 687-3937.

What is Errol Grannum's specialty?

The primary specialty registered for this NPI is Ophthalmology with taxonomy code 207W00000X.

Is Errol Grannum enrolled in Medicare?

Yes. Errol Grannum is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

What insurance does Errol Grannum accept?

Health plans from Blue Cross and Blue Shield of Texas, Molina Healthcare and UnitedHealthcare list Errol Grannum as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

Is Errol Grannum affiliated with any hospitals?

According to CMS data, Errol Grannum is affiliated with Rio Grande Regional Hospital.

When was this NPI record last updated?

The NPPES record for Errol Grannum was last updated on July 8, 2007. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 19 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.