Nereida Diaz-Johnson, MD

Medicare activity in 2024

Official CMS public-use data for Nereida Diaz-Johnson, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Most frequent services

1. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)209 services
2. Chronic care management services, first 20 minutes of clinical staff time directed by health care professional, per calendar month (99490)173 services
3. Injection of drug or substance under skin or into muscle (96372)101 services
4. Office or other outpatient visit for the evaluation and management of established patient that may not require presence of healthcare professional (99211)88 services
5. Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report (93000)86 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

• High blood pressure75%
• High cholesterol75%
• Arthritis42%
• Diabetes39%
• Ischemic heart disease26%
• Asthma21%

Hospitals where Nereida Diaz-Johnson works

Medicare's Facility Affiliation Data lists Nereida Diaz-Johnson at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

• Morristown Medical CenterMorristown, NJ · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 310015
• Overlook Medical CenterSummit, NJ · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 310051

Practice locations

Addresses where Nereida Diaz-Johnson is enrolled with Medicare (CMS data updated October 2, 2026).

• 2333 Morris Ave, Suite A109Union, NJ 07083 (908) 688‑5000

Group practices

Medicare enrollment lists Nereida Diaz-Johnson as a member of this group (CMS data updated October 2, 2026).

• Union Medical Group, LLC2 clinicians in the group

Specialties

• Internal Medicineprimary

Find other Internal Medicine doctors in New Jersey →

Other internal medicine doctors in Union

Clinicians with the same Medicare primary specialty in Union, NJ — not a recommendation.

• Jacqueline A. Fernandez, MD
• Pranathi R. Mandadi, MD
• Tariq Mahmood, MD
• Corina D. Smighelschi, MD
• Eric J. Williams, MD
• Omonuwa Adah, MD
• Walead Latif, MD
• Clark Philogene, MD

All internal medicine doctors in Union →

Other clinicians in Union Medical Group, LLC

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

• Clark Philogene, MD

Clinician information

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
6. Medicare Care Compare — official Medicare tool to look up clinicians