Mastering CMS 1500 Item 20: Billing Lab Services & Purchased Diagnostic Tests for Proper Reimbursement

Successfully mastering CMS 1500 Item 20 is not merely a matter of checking a box; it’s a critical component of accurate medical billing that directly impacts your organization’s reimbursement for laboratory services and purchased diagnostic tests. In the complex world of healthcare revenue cycle management, errors in this seemingly small field can lead to significant claim denials, delayed payments, and compliance headaches. This comprehensive guide, crafted by RCM experts, will demystify Item 20, providing you with the authoritative knowledge and practical strategies needed to ensure your claims are processed correctly the first time, every time. We’ll delve into the nuances of billing for services performed by outside labs, the intricate relationship with other claim fields, and the specific requirements for various diagnostic tests, empowering your billing team to navigate these challenges with confidence and precision.

Quick Reference Guide

Understanding the core principles of Item 20 is essential for any billing professional. This quick reference guide provides a snapshot of key codes, rules, and examples to help you make informed decisions when completing the CMS 1500 form.

CMS 1500 Field	Description	Key Rule/Guidance	Example Scenario
Item 20: Outside Lab?	Indicates if services were performed by an outside laboratory.	YES: Check if the lab service was performed by an entity other than the billing provider and the billing provider purchased the service. NO: Leave blank if the lab service was performed by the billing provider or if it’s not a lab service.	A physician’s office (billing provider) sends a patient’s blood sample to an independent clinical lab for analysis. The physician’s office will bill for the lab service.
Item 20: Charges	The actual charge for the purchased lab service.	Enter the amount the billing provider paid the outside lab. This amount should be reflected in the total charges (Item 21) and the payment requested (Item 28).	The independent lab charged the physician’s office $50 for the blood test. “$50.00” would be entered here.
Item 32: Service Facility Location Information	Where the service was actually rendered.	Enter the name, address, and NPI of the facility where the lab service was performed. Crucial for purchased diagnostic tests and outside labs.	The independent lab’s name, address, and NPI.
CPT Code Example (Lab)	Common lab procedure codes.	80053 (Comprehensive Metabolic Panel) 82947 (Glucose; quantitative, blood, except reagent strip) 87040 (Culture, bacterial; blood, any source, except urine, stool, wound, or other body fluid)	Billing for a routine blood test.
CPT Code Example (Purchased Diagnostic Test)	Common diagnostic imaging/testing codes.	70450 (CT head or brain, without contrast) 71045 (Radiologic examination, chest; single view) 93000 (Electrocardiogram, routine ECG with at least 12 leads; with interpretation and report)	Billing for an MRI interpretation performed by an outside radiologist.
Modifier 90	Reference (Outside) Laboratory.	Used when the billing provider sends a specimen to an outside lab for testing and bills for the service. Indicates the service was performed by a party other than the billing provider.	Physician’s office bills 80053-90.
Modifier 26	Professional Component.	Used when the physician provides only the interpretation and report for a diagnostic test. The technical component (TC) is performed by another entity.	Radiologist bills 70450-26 for interpreting a CT scan performed at a hospital.
Modifier TC	Technical Component.	Used when the facility or provider performs only the technical portion of a diagnostic test (e.g., operating equipment, providing supplies).	An independent diagnostic testing facility (IDTF) bills 70450-TC for performing the CT scan.

Detailed Breakdown

The intricacies of billing for lab services and purchased diagnostic tests extend far beyond a simple checkbox. A deep understanding of each relevant field on the CMS 1500 form, coupled with an awareness of payer-specific rules, is paramount for achieving proper reimbursement. This section will meticulously dissect these elements, providing the authoritative guidance you need. For more in-depth guidance on specific modifier usage and complex billing scenarios, you might find valuable resources on site:cms1500claimbilling.com.

Understanding CMS 1500 Item 20: The “Outside Lab” Indicator

Item 20 on the CMS 1500 form is titled “Outside Lab?” and has two distinct parts: a “YES” checkbox and a field for “CHARGES.” This item is specifically designed to identify situations where the billing provider (the entity submitting the claim) is billing for a laboratory service that was actually performed by a different, independent laboratory.

When to Check “YES” and Enter Charges:

Purchased Lab Services: If your practice or facility orders a lab test, sends the specimen to an independent clinical laboratory, and then bills the payer for that lab service, you must check “YES” in Item 20.

The “Charges” Field: Immediately below the “YES” checkbox, you must enter the actual amount your practice paid the outside laboratory for that specific service. This is crucial for transparency and compliance. It’s not the amount you’re charging the patient or payer, but your cost.

When to Leave Item 20 Blank:

In-Office Lab Services: If your practice performs the lab test in its own CLIA-certified laboratory, Item 20 should be left blank. You are the performing provider, not purchasing the service from an outside entity.

Non-Lab Services: Item 20 is exclusively for lab services. If you are billing for physician office visits, procedures, or diagnostic tests (e.g., X-rays, MRIs) that are not considered lab services, leave Item 20 blank.

Visual Aid Description: Imagine a screenshot of the CMS 1500 form, specifically highlighting Item 20. The “YES” box would be checked, and a dollar amount (e.g., “50.00”) would be clearly visible in the “CHARGES” field. This visual reinforces the direct relationship between the “YES” indicator and the cost incurred by the billing provider.

The Critical Link: Item 32 and Place of Service (POS) Codes

While Item 20 identifies if a lab service was purchased, Item 32 (“Service Facility Location Information”) specifies where the service was physically performed. These two fields work in tandem, especially for purchased diagnostic tests and outside lab services.

Item 32: Service Facility Location Information

Name and Address: You must enter the name and full address of the facility where the lab test or diagnostic service was actually rendered. This is often the independent lab’s address or the diagnostic imaging center’s address.

NPI of Service Facility: Crucially, Item 32a requires the National Provider Identifier (NPI) of the performing* facility. This is not your billing NPI (Item 33a) but the NPI of the entity that physically performed the service.

Importance: Incorrect or missing information in Item 32 is a leading cause of denials, as payers need to verify the legitimacy and location of the service.

Visual Aid Description: Picture a screenshot of CMS 1500 Item 32. The name of an independent lab (e.g., “Apex Clinical Labs”), its street address, city, state, and zip code would be filled in. Below that, in Item 32a, the lab’s NPI would be clearly visible. This visually connects the “where” with the “who” for the performing entity.

Place of Service (POS) Codes

Item 24B: The Place of Service (POS) code in Item 24B is vital. For purchased lab services or diagnostic tests, the POS code should reflect where the patient received the service*.

POS 81 (Independent Laboratory): Often used when a specimen is sent to an independent lab.

POS 11 (Office): If the billing provider’s office is also the performing facility for a lab test.

POS 19 (Off Campus-Outpatient Hospital) / POS 22 (On Campus-Outpatient Hospital): For services performed in hospital outpatient settings.

POS 12 (Home): For certain home health services, including some lab draws.

Consistency: The POS code must be consistent with the information provided in Item 32. If Item 32 lists an independent lab, POS 81 is typically appropriate.

Modifiers: The Language of Specificity

Modifiers provide additional information about a service or procedure, clarifying circumstances that alter its payment. For lab services and purchased diagnostic tests, specific modifiers are indispensable.

Modifier 90: Reference (Outside) Laboratory

Usage: Attach Modifier 90 to the CPT code for a lab service when the billing provider (e.g., physician’s office) sends the specimen to an outside laboratory for testing and then bills the payer for that test.

Example: A primary care physician’s office draws blood, sends it to “LabCorp” for a Comprehensive Metabolic Panel (CPT 80053), and then bills the insurance. The claim line would be `80053-90`. Item 20 would be “YES” with the charge paid to LabCorp, and Item 32 would list LabCorp’s information.

Modifiers 26 (Professional Component) and TC (Technical Component)

Diagnostic Tests (e.g., Radiology, Cardiology): Many diagnostic tests have two components:

Technical Component (TC): Covers the equipment, supplies, and technical staff.

Professional Component (26): Covers the physician’s interpretation and report.

Global Billing: When one entity performs both the technical and professional components, no modifier is needed (this is “global billing”).

Split Billing:

Modifier 26: Used by the physician who performs only the interpretation and report (e.g., a radiologist interpreting an MRI performed at a hospital). The claim line would be `70551-26`.

Modifier TC: Used by the facility or provider who performs only the technical portion (e.g., an independent diagnostic testing facility (IDTF) performing the MRI scan). The claim line would be `70551-TC`.

Purchased Diagnostic Test Scenario: If a physician’s office purchases the technical component of a diagnostic test (e.g., an X-ray) from an outside facility and then bills for the global service (including their own interpretation), they would bill the CPT code without a modifier, but Item 32 would list the performing facility’s information. If they only bill for their interpretation, they’d use Modifier 26.

National Provider Identifiers (NPIs)

NPIs are critical for identifying all parties involved in a healthcare service.

Billing Provider NPI (Item 33a): Your organization’s NPI, the entity submitting the claim.

Rendering Provider NPI (Item 24J): The NPI of the individual physician or non-physician practitioner who performed or supervised the service.

Service Facility NPI (Item 32a): As discussed, the NPI of the facility where the service was physically rendered (e.g., the independent lab or diagnostic center).

State-Specific and Payer-Specific Requirements

While federal CMS guidelines provide a strong foundation, it’s crucial to remember that billing rules can vary significantly:

State Medicaid Programs: Each state’s Medicaid program may have unique requirements for billing purchased services, specific CPT/HCPCS codes, or modifier usage. Always consult your state’s Medicaid provider manual.

Commercial Payers: Commercial insurance companies often have their own policies, which can sometimes differ from Medicare. Some payers might have specific forms, require prior authorization for certain tests, or have different rules for Modifier 90 or split billing. Always check the payer’s provider manual or website.

CLIA Waivers: For in-office lab testing, ensure your practice has the appropriate Clinical Laboratory Improvement Amendments (CLIA) certification or waiver. This information is often required by payers.

Staying updated on these variations is paramount. Regularly reviewing payer bulletins and participating in professional billing forums (like those often discussed on site:cms1500claimbilling.com) can help you avoid costly errors.

Real-World Billing Scenarios & Patient Status Changes

Let’s walk through several common scenarios to solidify your understanding of Item 20 and related fields. These examples highlight how patient status and service location impact billing.

Scenario 1: Physician’s Office Bills for Purchased Lab Service

Situation: Dr. Smith’s office draws blood from a patient, sends it to “Central Lab Services” (an independent lab) for a complete blood count (CBC – CPT 85025). Dr. Smith’s office receives the results and bills the patient’s insurance.

CMS 1500 Completion:

Item 20 “Outside Lab?”: YES

Item 20 “Charges”: Enter the amount Dr. Smith’s office paid Central Lab Services (e.g., $15.00).

Item 24D (CPT/HCPCS): 85025

Item 24E (Modifier): 90

Item 24B (POS): 81 (Independent Laboratory)

Item 32 (Service Facility Name/Address): Central Lab Services’ name and address.

Item 32a (Service Facility NPI): Central Lab Services’ NPI.

Item 33a (Billing Provider NPI): Dr. Smith’s office NPI.

Scenario 2: Physician’s Office Performs In-Office Lab Service

Situation: Dr. Smith’s office has a CLIA-waived lab and performs a rapid strep test (CPT 87880) in-house for a patient.

CMS 1500 Completion:

Item 20 “Outside Lab?”: Leave blank.

Item 20 “Charges”: Leave blank.

Item 24D (CPT/HCPCS): 87880

Item 24E (Modifier): Leave blank (unless other specific circumstances apply).

Item 24B (POS): 11 (Office)

Item 32 (Service Facility Name/Address): Dr. Smith’s office name and address (or leave blank if same as Item 33).

Item 32a (Service Facility NPI): Dr. Smith’s office NPI (or leave blank if same as Item 33a).

Item 33a (Billing Provider NPI): Dr. Smith’s office NPI.

Scenario 3: Radiologist Bills for Interpretation of Purchased Diagnostic Test

Situation: A patient has an MRI of the knee (CPT 73721) performed at “City Hospital Outpatient Department.” Dr. Jones, an independent radiologist, interprets the MRI images and provides a report. Dr. Jones’s practice bills for the interpretation.

CMS 1500 Completion (Dr. Jones’s Practice):

Item 20 “Outside Lab?”: Leave blank (not a lab service).

Item 24D (CPT/HCPCS): 73721

Item 24E (Modifier): 26 (Professional Component)

Item 24B (POS): 22 (On Campus-Outpatient Hospital) or 19 (Off Campus-Outpatient Hospital), depending on the hospital’s designation.

Item 32 (Service Facility Name/Address): City Hospital Outpatient Department’s name and address.

Item 32a (Service Facility NPI): City Hospital’s NPI.

Item 33a (Billing Provider NPI): Dr. Jones’s practice NPI.

Scenario 4: Independent Diagnostic Testing Facility (IDTF) Bills for Technical Component

Situation: “Advanced Imaging Center” (an IDTF) performs the technical component of an MRI of the knee (CPT 73721) for a patient. The images are sent to an outside radiologist for interpretation. Advanced Imaging Center bills for the technical component.

CMS 1500 Completion (Advanced Imaging Center):

Item 20 “Outside Lab?”: Leave blank.

Item 24D (CPT/HCPCS): 73721

Item 24E (Modifier): TC (Technical Component)

Item 24B (POS): 11 (Office) or 19/22 if part of a hospital system.

Item 32 (Service Facility Name/Address): Advanced Imaging Center’s name and address (or leave blank if same as Item 33).

Item 32a (Service Facility NPI): Advanced Imaging Center’s NPI (or leave blank if same as Item 33a).

Item 33a (Billing Provider NPI): Advanced Imaging Center’s NPI.

Common Denial Codes & Step-by-Step Appeal Instructions

Despite meticulous efforts, denials can occur. Understanding common denial codes related to Item 20 and purchased services, along with a robust appeal process, is crucial for revenue recovery.

Common Denial Codes and Their Meanings:

CO-16: Claim/service lacks information or has submission/billing error(s).

Relevance to Item 20: This is a broad denial, but it frequently appears when Item 20 is incorrectly completed (e.g., “YES” checked but no charges, or charges entered but “YES” not checked). It can also indicate missing or incorrect information in Item 32 (service facility details).

Action: Review Item 20 and Item 32 carefully. Ensure the “YES” checkbox aligns with the “CHARGES” amount and that Item 32 contains the correct performing facility’s name, address, and NPI.

M86: Not covered when performed in this setting.

Relevance to Item 20: Often related to an incorrect Place of Service (POS) code (Item 24B) for the type of service billed, or a mismatch between the POS and the performing facility in Item 32. For instance, billing a lab service with POS 11 (Office) when it was performed by an independent lab (should be POS 81).

Action: Verify the POS code is appropriate for where the service was rendered and consistent with Item 32.

PR-96: Non-covered charges.

Relevance to Item 20: While not directly tied to Item 20 completion, this can occur if the payer’s policy does not cover purchased lab services from certain types of facilities, or if the medical necessity for the lab test is not adequately documented.

Action: Review the patient’s benefits and the payer’s medical policies. Ensure medical necessity is clearly documented in the patient’s record.

N55: Missing/invalid NPI.

Relevance to Item 20: This often points to an issue with the NPI in Item 32a (performing facility NPI) or Item 24J (rendering provider NPI).

Action: Double-check all NPIs on the claim against official NPI registries.

B13: Previously paid.

Relevance to Item 20: This can happen if both the billing provider and the performing lab/facility submit a claim for the same* service. This highlights the importance of clear communication and understanding who is responsible for billing the global, technical, or professional component.

Action: Investigate if the performing facility also billed for the service. Adjust your claim or coordinate with the performing facility.

Step-by-Step Appeal Instructions:

1. Identify the Denial Reason: Carefully read the Explanation of Benefits (EOB) or Electronic Remittance Advice (ERA) to understand the exact denial code and description. 2. Review the Claim: Pull up the original claim submitted and compare it against your internal records and the payer’s guidelines. Focus on Item 20, Item 24B, Item 24D (CPT/HCPCS with modifiers), Item 32, and all NPIs. 3. Gather Supporting Documentation:

Medical record documentation supporting medical necessity.

Lab requisition forms.

Invoice from the outside lab/diagnostic facility (if applicable for purchased services).

Payer-specific policy documents that support your billing.

CLIA certificate/waiver (for in-office labs).

4. Draft an Appeal Letter:

Clearly state the patient’s name, account number, date of service, and claim number.

Reference the denial code and explain why you believe the denial is incorrect.

Cite specific payer policies or CMS regulations that support your position.

Clearly outline the corrections made to the claim (if resubmitting) or why the original claim was correct.

Request a specific action (e.g., reprocessing the claim, full payment).

5. Submit the Appeal:

Follow the payer’s specific appeal process and deadlines. This usually involves mailing a written appeal letter with all supporting documentation. Some payers allow online appeals.

Keep a copy of everything submitted for your records.

6. Track and Follow Up: Note the appeal submission date and follow up with the payer within their stated timeframe for appeal resolution. By adopting a proactive and informed approach to CMS 1500 Item 20, your billing operations can significantly reduce denials, accelerate reimbursement, and maintain robust compliance. The details matter, and mastering them is the hallmark of an expert RCM professional.

FAQ: Common Questions Answered

What is considered a ‘purchased diagnostic test’ for CMS 1500 Item 20?

For the purpose of CMS 1500 Item 20, a ‘purchased diagnostic test’ refers specifically to a laboratory service that the billing provider did not perform themselves. Instead, the billing provider sent the patient’s specimen or referred the patient to an independent clinical laboratory or other diagnostic facility, paid that facility for the service, and is now billing the payer for that service. The key distinction is that the billing provider is acting as a pass-through entity, having incurred a cost for the lab service from an external vendor.

When should ‘Yes’ or ‘No’ be marked in CMS 1500 Item 20 for lab services?

You should mark ‘YES’ in CMS 1500 Item 20 if the laboratory service was performed by an entity other than your billing provider, and your organization purchased that service from the outside lab. This indicates that you are billing for a service you acquired from another facility. Conversely, you should leave Item 20 blank (which is interpreted as ‘NO’) if the lab service was performed directly by your billing provider’s own facility, or if the service being billed is not a laboratory service at all. Accurate selection is crucial for proper reimbursement and compliance.

How does CMS 1500 Item 20 directly impact the completion of Item 32?

CMS 1500 Item 20 has a direct and critical impact on Item 32, which specifies the Service Facility Location Information. If Item 20 is marked ‘YES’ (indicating an outside lab performed the service and it was purchased), then Item 32 must reflect the name, address, and NPI of that outside laboratory where the service was physically rendered, not the billing provider’s facility. This ensures that the payer understands where the service actually took place, which is vital for proper claims processing, especially for services that are location-dependent or require specific facility accreditations. Misalignment between Item 20 and Item 32 is a common cause of claim denials.

What are the financial and compliance risks associated with incorrect completion of CMS 1500 Item 20?

Incorrectly completing CMS 1500 Item 20 carries significant financial and compliance risks. Financially, errors can lead to immediate claim denials, requiring time-consuming resubmissions and appeals, which directly impacts your revenue cycle and cash flow. Delayed payments are also common as payers investigate discrepancies. From a compliance perspective, misrepresenting whether a lab service was performed in-house or purchased from an outside entity can be viewed as fraudulent billing. This can trigger audits, result in substantial penalties, recoupments, and even exclusion from federal healthcare programs. Accurate completion ensures transparency, adherence to payer guidelines, and safeguards your organization’s financial health and reputation.

External Resources & Authority Links

• For more detailed insights, refer to the official CMS Medicare guidelines.
• For more detailed insights, refer to the CMS guidelines.