CPT code 87040 – Blood culture, aerobic bacteria

Key takeaways

CPT code 87040 covers one bacterial blood culture set, aerobic and anaerobic bottles together, with isolation and presumptive identification.

Bill one unit per separately collected set, and record the collection time and site for each one.

Only the performing laboratory bills 87040, and Medicare pays it on the Clinical Laboratory Fee Schedule.

Missing ICD-10 links and undocumented second units are common reasons 87040 claims get denied.

Pabau’s claims management software checks eligibility, sends claims through Claim.MD and tracks 835 remittances in one place.

CPT code 87040 bills one blood culture set, both bottles included

CPT code 87040 is the code for a bacterial blood culture with isolation and presumptive identification of any organisms that grow. Its official descriptor names aerobic culture and adds “includes anaerobic culture, if appropriate.” So the standard two-bottle set, one aerobic and one anaerobic, is one unit of 87040.

The American Medical Association maintains the CPT code set. 87040 sits in the Microbiology subsection (87001-87999) of the Pathology and Laboratory chapter.

“Presumptive identification” means the lab grew the organism and made a preliminary ID. Susceptibility testing is a separate step, reported with 87184 or 87186. Definitive identification of an aerobic isolate by additional methods goes to 87077, one unit per isolate.

What 87040 includes, and what needs its own code

The fastest way to code a blood culture order correctly is to know where 87040 stops. Use this table when the requisition lists more than the culture itself.

The draw itself sits outside 87040. Venipuncture is reported separately with 36415 by whoever collects the specimen, whether that is the lab or the practice.

How an 87040 claim moves from draw to payment

An 87040 claim passes through five hand-offs before it is paid, and each one has a slip that can turn into a denial. The flow below maps them.

1. Order. The clinician documents why bacteremia is suspected and how many sets to draw. A bare “blood cultures x2” gives the claim nothing to prove medical necessity.
2. Collection. Whoever draws the blood records the time, site and bottle types for each set. That record is what supports a second unit later.
3. Culture. The lab incubates both bottles and reports an organism or a final no-growth result. One set equals one unit of 87040, however many bottles it holds.
4. Claim. The performing lab bills 87040 per set, links a covered ICD-10 code and adds its CLIA number. A hospital outpatient lab uses the UB-04, and an independent lab uses the CMS-1500 or 837P.
5. Payment. Medicare pays from the Clinical Laboratory Fee Schedule. The 835 remittance carries the CARC and RARC codes that explain any denial.

Medical necessity starts with the reason in the order note

Payers cover 87040 when the record makes bacteremia a reasonable suspicion. Medicare contractors and commercial plans expect the ordering note to name one of these scenarios.

• Suspected bacteremia: Fever above 101°F (38.3°C) with chills, rigors or hypotension and no identified source.
• Sepsis workup: Sepsis criteria met, typically with two sets drawn before antibiotics, per Surviving Sepsis Campaign guidance.
• Fever of unknown origin (FUO): Prolonged fever with no clear cause after initial evaluation.
• Immunocompromised patients: Active chemotherapy, a solid organ or bone marrow transplant, HIV with a low CD4 count, or long-term corticosteroid use.
• Prosthetic device infection: Suspected infection of an implanted cardiac device, prosthetic joint or vascular graft.
• Endocarditis workup: A new murmur, positive echocardiographic findings, or Osler nodes or Janeway lesions.

Sepsis protocols often produce two or more sets drawn minutes apart. Following the CPT per-set convention, each separately collected set can be billed as its own unit of 87040.

That only holds up with paperwork behind it. The lab report needs the collection times and set count, and the order note needs the clinical reason. Without them, a second unit on the same date tends to come back as a duplicate-service denial.

ICD-10 codes that support 87040 medical necessity

Billing units: One per set, never one per bottle

CPT code 87040 is billed per blood culture set. A standard set is two bottles from a single venipuncture, one aerobic and one anaerobic. Both bottles sit inside that one unit, so the anaerobic bottle is never billed as 87075.

Here is how that plays out. A patient arrives in the emergency department with a 102.4°F fever and rigors, and the physician orders two sets. The nurse draws set one from the left arm at 2:05 PM and set two from the right arm at 2:20 PM. That is four bottles and two units of 87040.

Two units from a single draw is a coding error, and payers catch it through Medically Unlikely Edits (MUE) or a duplicate-service denial. When the second set is legitimate, payers differ on the modifier. Many expect 59 or XS on the second line, while some ask for 91, so check the payer’s policy first.

Who bills 87040? The lab that runs the culture

The performing laboratory bills CPT code 87040, never the ordering physician. It is a technical laboratory code with no professional component and no TC/26 split, so the ordering physician has no role to bill under it.

The claim form and payment route depend on which kind of lab ran the culture.

• Hospital outpatient lab? It bills on a UB-04 under OPPS. Lab tests there are paid on the CLFS or packaged into other services, not as separate APC payments.
• Independent reference lab? It bills on a CMS-1500 or 837P and is paid on the CLFS.
• Physician office lab? It can bill 87040 when it performs the culture itself and holds a CLIA certificate that covers the test.

A physician who submits 87040 on a professional claim will see it rejected, because the physician did not perform the test.

Medicare pays 87040 from the lab fee schedule

Under the Medicare Clinical Laboratory Fee Schedule (CLFS), 87040 pays a single national rate. CMS updates CLFS rates every year, and PAMA market-based pricing can move them. Check the current figure in the CMS Clinical Laboratory Fee Schedule before quoting a rate to a practice or payer.

• No prior authorization: Medicare lab services on the CLFS typically need none. Commercial plans vary, so confirm with each one.
• MAC coverage rules: Some MACs publish local coverage determinations (LCDs) that limit which ICD-10 codes are covered. Check your MAC’s LCD for lab services.
• Commercial payer rates: Most commercial contracts pay a percentage of the Medicare CLFS rate, and terms vary widely.
• OPPS vs CLFS: Hospital outpatient labs bill under OPPS, but their lab tests are paid on the CLFS or packaged into other services. They do not get separate APC payments.

Six denials that hit 87040, and how to head them off

87040 denials cluster around a handful of root causes. Each one can be prevented before the claim leaves the building.

When a claim comes back, match its CARC and RARC to the right category in our guide to medical billing denial codes. That tells your team whether to correct and resubmit or to appeal.

Before you submit: A six-point checklist for clean 87040 claims

A clean claim for 87040 needs the order note and the lab report to agree. Run through this list while both are on file, not after a denial arrives.

• Indication on the order: The note names the clinical reason, such as “fever 102.4°F with rigors, suspected bacteremia,” and the number of sets.
• Collection details: The lab report shows the date, time, site and bottle types for each set.
• Units match sets: One unit per separately collected set, never one per bottle.
• Final result: The report carries an identified organism or a final no-growth result per the lab’s protocol.
• ICD-10 linked to the line: The covered diagnosis points to the 87040 line, not only to the E/M encounter.
• Place of service: POS 11 (office), POS 22 (outpatient hospital) or POS 81 (independent laboratory), as appropriate.

The superbill behind the order should also carry the ordering provider’s NPI, the lab’s CLIA number and the date of service. Electronic claims check all three, and a missing one triggers a front-end rejection before adjudication.

The neighboring codes that get mixed up with 87040

Blood culture orders often share a requisition with other microbiology codes. Coding a urine specimen as 87040, or a blood specimen as 87086, is a material error that this table helps you avoid.

LOINC mapping is where blood culture orders get miscoded

Many laboratory information systems (LIS) assign CPT codes automatically from LOINC test orders, so a mismatch between the two is a common source of miscoding. The LOINC database has several codes for blood culture results, and LOINC publishes no official CPT crosswalk.

LOINC codes are versioned, so re-check your LIS mappings against the current release whenever the LIS or EHR is upgraded. A stale mapping can attach a wrong-specimen CPT code to blood culture orders, an error that is easy to miss at volume.

How Pabau keeps 87040 claims clean from eligibility to remittance

Many lab billing teams check eligibility in one portal, build claims in another and reconcile payments by hand. Each switch between systems is a chance to drop a collection time or a diagnosis pointer.

Pabau, the practice management platform we build, brings those steps into one place. Its claims management software runs real-time eligibility checks and sends CMS-1500 and 837P claims through the Claim.MD clearinghouse to thousands of US payers.

Remittances come back as 835 ERAs, so your team sees each CARC code next to the 87040 line it applies to. Payments can then be reconciled against expected CLFS rates without logging into individual payer portals.

Send cleaner 87040 claims with less portal work

Pabau checks eligibility, sends blood culture claims through the Claim.MD clearinghouse and tracks 835 remittances, so your team spends less time in payer portals.

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Conclusion

Blood culture billing turns on one count, and it is sets rather than bottles. Record a time and site for every set at the draw. Do that, and 87040 becomes one of the simpler lab codes to get paid.

The work worth doing this week is upstream of the claim. Pull a sample of last month’s 87040 claims and compare each one with its lab report. Where units and collection records disagree, fix the order template and the collection checklist before you touch the claim scrubber.

Book a demo to see how Pabau checks eligibility, submits your 87040 claims and tracks every remittance in one place.

Continue your research

Need to understand how clearinghouse submission works for lab codes? Medical claims clearinghouse guide explains how payer routing, rejection codes, and ERA processing work for laboratory claims.

Getting NCCI edits on microbiology codes? Medical billing compliance overview covers how NCCI edits work and what documentation supports modifier use.

Want to understand how 835 remittance data maps to denial reasons? Electronic remittance advice explained breaks down ERA file structure, CARC codes, and how to read payer explanation of benefits data.

Building a denial workflow for lab claims? Denial management in healthcare walks through tracking, appealing and preventing denied claims.

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