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Edit this profileAt a glance
- 910 N Eisenhower Ave, Mason City, IA 50401
About Dr. Johnson
Mark C. Johnson, MD practices endocrinology in Mason City, IA. Mark is a 1977 graduate of University of Iowa, Rj & L Carver College of Medicine. Mark is also listed as specializing in internal medicine. Medicare claims data shows Mark provided 3,849 services to 2,269 patients. The services billed most often include routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only, established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more, and visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient'. The provider's National Provider Identifier (NPI) is 1013923127.
Factual summary compiled by Guide.md from public records; not written by this provider.
Education & Training
Specialty
Credentials & Licensing
Medicare information
Exactly as CMS reports it (National Downloadable File, Opt-Out Affidavits, Order & Referring). Not an insurance directory; confirm coverage with the office.
Contact Information
- (641) 428-7799
- Email not available
Practice Locations
910 N EISENHOWER AVE
Mason City, IA 50401
Conditions Commonly Evaluated or Treated
Within Endocrinology, Diabetes and Metabolism generally. Availability varies by clinician, training and location — this profile has not been claimed, so nothing here is a personal claim by the provider.
Conditions
Most searched conditions
- Diabetes
- Hyperthyroidism
- Hypothyroidism
- Obesity
- Osteoporosis
- PCOS
- Thyroid problems
Adrenal
- Low sodium or electrolyte imbalance
Adrenal disorders
- Adrenal Fatigue
- Adrenal gland tumor
- Adrenal mass
- Cushing's Syndrome
Blood sugar disorders
- Diabetic neuropathy
- Gestational diabetes
- Low Blood Sugar
- Prediabetes
Bone and calcium disorders
- High calcium
- Low Calcium
- Vitamin D deficiency
Bones
- Soft Bones
Diabetes
- Dangerous high blood sugar
- Diabetic retinopathy
- Kidney disease from diabetes
Endocrine tumors
Hormone disorders
- Early or delayed puberty
- Excess facial or body hair
- Gynecomastia
- Perimenopause
- Testosterone deficiency
Hormones
Metabolic disorders
- High cholesterol
- Metabolic syndrome
Metabolism
- Fatty liver disease
- Insulin Resistance
- Unexplained Weight Gain
Parathyroid
Pituitary
- Acromegaly
- Adult Growth Hormone Deficiency
- Underactive Pituitary Gland
Pituitary disorders
- Extreme Thirst and Urination
- High Prolactin
- Pituitary Tumor
- Short stature and growth concerns
Thyroid
- Thyroiditis
Thyroid disorders
- Goiter
- Graves' Disease
- Hashimoto's Disease
- Thyroid cancer
- Thyroid eye disease
- Thyroid nodules
Procedures & services
Most searched procedures
- Hormone replacement therapy
- Insulin pump management
- Thyroid ultrasound
- Weight loss management
Adrenal
- 24-Hour Urine Cortisol Test
- Aldosterone and Renin Blood Test
- Urine Metanephrines Test
Adrenal evaluations
- Adrenal Gland Suppression Test
- Cortisol Testing
Blood sugar management
- Continuous Glucose Monitor Placement
- Diabetes Screening and A1C Test
- Glucose screening test
Bone evaluations
- Bone Density Scan Referral
- Parathyroid Hormone Test
Bone treatments
- Bisphosphonate Infusion for Bones
- Bone Building Injections
Diabetes
- Automated Insulin System Setup
- Blood Ketone Monitoring
- C-Peptide Test
- Continuous Glucose Monitor Data Review
- Medical nutrition therapy
- Starting Insulin Therapy
Diabetes education
- Diabetes Self-Management Education
Diabetes preventive care
- Diabetic Foot Care
Genetic evaluations
- Genetic Testing for Endocrine Tumors
Hormone treatments
- Estrogen and Progesterone Therapy
- Growth Hormone Injections
- Hormone Replacement Therapy Consultation
Hormones
- Gender-affirming care consultation
Metabolic evaluations
- Cholesterol and Lipid Blood Panel
Metabolism
- Fasting Insulin Test
Parathyroid
- Parathyroid Scan
Pituitary
- Growth Hormone Stimulation Test
Pituitary evaluations
- Prolactin Blood Test
- Water Deprivation Test
Thyroid
- Thyroid Cyst Alcohol Ablation
- Thyroid Uptake and Scan
Thyroid procedures
- Radioactive Iodine Treatment
- Thyroid Antibody Testing
- Thyroid Blood Test
- Thyroid Medication Adjustment
- Thyroid Nodule Biopsy
- Thyroid Nodule Radiofrequency Ablation
Weight & Metabolism
- Weight loss medication consult
Procedures Most Often Billed to Medicare
3,849 services · 2,269 patients · 7 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only | Treatment | 93010 |
1,381 | More than most peers in Endocrinology |
| Continuous monitoring of blood sugar level in tissue fluid using sensor under skin with interpretation and report | Treatment | 95251 |
379 | More than most peers in Endocrinology |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
987 | More than most peers in Endocrinology |
| Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient' | Billing code | G2211 |
828 | More than most peers in Endocrinology |
| Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | Office visit | 99232 |
244 | More often than most peers in Endocrinology |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
17 | More than most peers in Endocrinology |
| Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more | Office visit | 99213 |
13 | Less often than most peers in Endocrinology |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Other endocrinology specialists at this location 1
Same specialty, same street address — most likely the same department or group.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
Trained at University of Iowa, Rj & L Carver College of Medicine 8
Other providers in the same specialty who trained at the same institution.
More connections — 8 related providers in 1 group
Class of 1977 at University of Iowa, Rj & L Carver College of Medicine 8
Providers who graduated from the same medical school in the same year.
Common questions
What kind of doctor is Dr. Johnson?
Dr. Johnson is an endocrinology in Mason City, IA. That is the designation recorded for this NPI in the federal registry.
NPI registry
What is Dr. Johnson's address?
Dr. Johnson is listed at 910 N Eisenhower Ave, Mason City, IA 50401. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with Dr. Johnson?
The number on file is (641) 428-7799. Contact the office directly to confirm availability and scheduling.
NPI registry
What is the NPI for Dr. Johnson?
Dr. Johnson's National Provider Identifier is 1013923127. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Dr. Johnson train?
Dr. Johnson attended University of Iowa, Rj & L Carver College of Medicine, graduating in 1977. This comes from the CMS National Downloadable File.
CMS public data
How much experience does Dr. Johnson have?
Dr. Johnson has 49 years experience. Calculated from a graduation year of 1977, reported in the CMS National Downloadable File.
CMS public data
What procedures does Dr. Johnson perform?
According to Medicare billing data, Dr. Johnson provides treatments such as routine electrocardiogram using at least 12 leads with interpretation and report only and continuous monitoring of blood sugar level in tissue fluid using sensor under skin with interpretation and report, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Is Dr. Johnson's profile verified?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Johnson. If this is you, claiming it is free.
Guide.md
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