When it comes to OB/GYN medical billing, accuracy is everything. A small coding mistake can lead to claim denials, delayed payments, or compliance risks.
One commonly used procedure code in gynecology is CPT Code 58100, which applies to endometrial biopsy procedures performed in office settings. However, many practices still struggle with correct usage, documentation, and modifier application.
👉 Struggling with frequent denials or underpayments? Rhino MDS helps practices reduce denials by up to 50% with expert billing support.
What is CPT Code 58100?
CPT Code 58100 refers to:
Endometrial sampling (biopsy), with or without endocervical sampling, is performed without cervical dilation.
This is a minor diagnostic procedure typically done in an office or outpatient setting. The provider collects tissue from the uterine lining (endometrium) to evaluate abnormalities.
Key Highlights:
- No cervical dilation required
- Includes endocervical sampling (if performed)
- Typically performed using a Pipelle or similar device
- Has a 0-day global period
Accurate coding starts with understanding procedure definitions — something our billing experts at Rhino MDS handle daily for OB/GYN practices.
Quick Overview of CPT 58100
| Attribute | Details |
| Procedure | Endometrial biopsy |
| Setting | Office / Outpatient |
| Cervical dilation | Not included |
| Global period | 0 days |
| Includes | Endometrial + endocervical sampling |
| Excludes | Pathology interpretation |
When to Use CPT Code 58100
CPT 58100 is appropriate when a provider performs a diagnostic endometrial biopsy without cervical dilation.
Common Clinical Indications:
- Abnormal uterine bleeding
- Postmenopausal bleeding
- Suspected endometrial hyperplasia
- Evaluation for endometrial cancer
- Abnormal imaging findings
- Hormonal therapy follow-up
Not sure if your coding aligns with payer rules? Rhino MDS audits your claims before submission to prevent costly errors.
When NOT to Use CPT Code 58100
Using the wrong CPT code is one of the top reasons for claim denials.
Avoid CPT 58100 in these scenarios:
- ❌ Cervical dilation is required → Use CPT 58120 (D&C)
- ❌ Procedure performed during hysteroscopy → Use CPT 58558
- ❌ Biopsy bundled under another procedure (NCCI edits)
Our team ensures correct code selection so your practice doesn’t lose revenue due to simple coding mistakes.
CPT 58100 vs 58120 vs 58558 (Key Differences)
Feature | CPT 58100 | CPT 58120 | CPT 58558 |
Procedure | Biopsy | Dilation & Curettage | Hysteroscopy + biopsy |
Cervical dilation | No | Yes | Yes |
Complexity | Low | Moderate | High |
Setting | Office | Facility | OR |
Bundling | Standalone | Standalone | Includes biopsy |
Choosing the wrong code here can directly impact reimbursement — Rhino MDS helps optimize coding accuracy across all OB/GYN procedures.
ICD-10 Codes Commonly Used with CPT 58100
Correct diagnosis coding is essential to support medical necessity.
Common ICD-10 Codes:
- N93.0 – Postcoital bleeding
- N93.8 – Other abnormal uterine bleeding
- N93.9 – Unspecified abnormal uterine bleeding
- N95.0 – Postmenopausal bleeding
We align CPT and ICD-10 coding to ensure maximum claim acceptance and faster reimbursements.
Documentation Requirements for CPT 58100
Strong documentation is your first defense against denials.
Billing Checklist:
- Clear reason for biopsy
- Confirmation of no cervical dilation
- Technique used (e.g., Pipelle)
- Tissue obtained and sent to pathology
- Patient tolerance and response
- Follow-up instructions
Incomplete documentation is a major denial trigger — Rhino MDS reviews documentation before claim submission to ensure compliance.
CPT 58100 Modifiers Explained (With Examples)
Modifier 25 – Significant E/M Service
Use when a separate, medically necessary evaluation is performed on the same day. 📌 Example: A patient presents with abnormal bleeding. The physician performs a full evaluation before deciding to proceed with a biopsy.Modifier 59 – Distinct Procedural Service
Used only when procedures are separate and non-overlapping. ⚠️ Do not use it to bypass bundling rules.Modifier XU – Unusual Non-Overlapping Service
Applies when the biopsy is completely independent of another procedure.Modifier 52 – Reduced Services Used when the procedure is partially completed or reduced. 👉 Incorrect modifier usage is one of the top causes of denials — our experts ensure every claim is modifier-optimized.
CPT Code 58100 Reimbursement Rates (2026 Update)
Medicare (Approximate Rates):
- Facility: ~$61
- Non-facility: ~$97
Commercial Insurance:
- Typically ranges between $120 – $170
Factors Affecting Payment:
- Geographic location
- Payer contracts
- Facility vs office setting
Global Period for CPT 58100 (0-Day Rule Explained)
CPT 58100 has a 0-day global period, meaning:
- Only same-day services are included
- Follow-up visits can be billed separately
- No 10-day post-op package applies
Understanding global periods correctly can unlock additional revenue opportunities — something we optimize for every client.
Real-World Billing Scenario (Avoid Denials)
✔ Correct Coding:
- CPT 58100 (biopsy)
- E/M code with Modifier 25
✔ Outcome:
- Clean claim submission
- Faster reimbursement
- No denial due to proper documentation
Common Billing Mistakes to Avoid
Even experienced billers make these errors:
- Using 58100 instead of 58120
- Missing documentation of no cervical dilation
- Incorrect modifier usage
- Billing biopsy separately during hysteroscopy
- Assuming a 10-day global period
Avoid these costly mistakes with a professional billing partner managing your revenue cycle.
Does CPT 58100 Include Pathology?
No — CPT 58100 only covers the tissue collection.
👉 Pathology interpretation must be billed separately by the pathology provider.
How to Reduce Denials for CPT 58100 Claims
✔ Best Practices:
- Ensure documentation completeness
- Match ICD-10 with clinical findings
- Validate modifier usage
- Review NCCI edits
Stop Losing Revenue to Claim Denials
If your practice is dealing with:
- Frequent claim denials
- Delayed reimbursements
- Coding inaccuracies
👉 Rhino MDS can help you:
- Reduce denials by up to 50%
- Improve cash flow
- Ensure accurate OB/GYN billing
Let your team focus on patient care — we’ll handle the billing.
Final Thoughts
CPT Code 58100 may seem simple, but incorrect usage can lead to denials, compliance issues, and lost revenue.
By focusing on:
- Accurate documentation
- Correct modifier usage
- Proper code selection
You can significantly improve your revenue cycle performance.
Frequently Asked Questions About Provider Credentialing
What is CPT code 58100 used for?
It is used for an endometrial biopsy performed without cervical dilation in an office or outpatient setting.
Does CPT 58100 include endocervical sampling?
Yes, it includes endocervical sampling when performed during the same procedure.
Can CPT 58100 and hysteroscopy be billed together?
Usually no. The hysteroscopy code typically includes the biopsy.
What is the global period for CPT 58100?
It has a 0-day global period.
What modifier is used with CPT 58100?
Modifier 25 is commonly used when a separate E/M service is performed.