Matthew Grelling, M.A. M.F.T.
NPI 1831239037 · Mental Health Counselor · Diamond Bar, CA
Matthew Grelling, M.A. M.F.T. is a Mental Health Counselor provider in Diamond Bar, CA (NPI 1831239037).
Provider details
- NPI number
- 1831239037
- Entity type
- Individual
- Primary specialty
- Mental Health CounselorBehavioral Health & Social Service Providers
- Credential
- M.A. M.F.T.
- Sex
- Male
- Sole proprietor
- Yes
- License
- MFT 35675 (CA)
Specialties & taxonomies
Behavioral Health & Social Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-02-07
- Last updated
- 2007-07-08
Frequently asked questions
- What is Matthew Grelling's NPI number?
- Matthew Grelling's National Provider Identifier (NPI) is 1831239037, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Matthew Grelling's specialty?
- Matthew Grelling is listed in the NPPES registry with a primary specialty of Mental Health Counselor (Behavioral Health & Social Service Providers).
- Where is Matthew Grelling located?
- Matthew Grelling's practice location on file with NPPES is 1111 Grand Ave Ste J, Diamond Bar, CA 91765-4172.
- What is Matthew Grelling's phone number?
- The practice phone number listed in the NPPES registry for Matthew Grelling is (951) 505-0019.
- Is Matthew Grelling's NPI active?
- Yes — Matthew Grelling's NPI (1831239037) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.