CPT code 01842: Anesthesia for forearm, wrist, and hand embolectomy

Key Takeaways

CPT code 01842 covers anesthesia for an embolectomy on the arteries of the forearm, wrist, and hand, and it carries 6 base units.

Medicare pays base units plus time units, multiplied by the locality conversion factor; physical status and qualifying circumstance modifiers must still be reported, but they carry Medicare status B, bundled, so they add no separate payment.

Modifier AA signals the anesthesiologist personally performed the service, while a CRNA billing under medical direction uses modifier QX, with rules that vary by payer and state.

Practice management software like Pabau checks that the required insurer fields are complete before a claim can be sent, and gives your billing team a live status view from submission through payment.

A patient arrives with a cold, pulseless hand, and the surgeon calls for an emergency embolectomy before the tissue dies. CPT code 01842 is the anesthesia code for that operation: an embolectomy on the arteries of the forearm, wrist, and hand. It carries 6 base units.

The code sits next to two lookalikes in the same family, 01840 and 01844, and Medicare pays it differently than the four-part formula many billers default to. Get the anatomy, the units, and the payer rules right, and the claim goes out clean the first time.

CPT code 01842: Definition and clinical description

CPT code 01842 is maintained by the American Medical Association (AMA) as part of the CPT code set. It falls within the anesthesia section, specifically the subsection covering procedures on arteries of the upper extremity. The official descriptor is: Anesthesia for procedures on arteries of forearm, wrist, and hand; embolectomy.

Clinical context: what is an embolectomy and why does anesthesia apply?

An embolectomy removes a blood clot or embolus that has lodged in an artery, blocking blood flow to the tissue downstream. In the upper extremity, this typically affects the radial or ulnar artery and presents as acute limb ischemia: the hand and fingers become pale, cool, and pulseless. Without prompt intervention, irreversible tissue damage occurs within hours.

Anesthesia is required because the procedure involves open arterial dissection or catheter-based clot removal under controlled surgical conditions. General or regional anesthesia (commonly an axillary nerve block or general endotracheal) is used depending on the patient’s status and the surgeon’s approach. CPT code 01842 captures the anesthesia service for this specific procedure and anatomical location, making it distinct from codes covering the same procedure at other vascular sites.

• Radial artery embolectomy: typically performed via a wrist incision
• Ulnar artery embolectomy: approached proximally or distally, through Guyon’s canal at the wrist
• Catheter-based (Fogarty catheter) technique: most common surgical method for clot retrieval
• Regional anesthesia alternative: brachial plexus block used when general anesthesia carries elevated risk

Billing CPT code 01842 correctly requires knowing the anatomical site operated on matches the forearm, wrist, and hand arteries. If the procedure is on a more proximal vessel (axillary or subclavian), a different anesthesia code applies. Surgical practice management platforms that integrate procedure documentation with billing can flag anatomical mismatches before claims are submitted.

How anesthesia units and billing work for CPT code 01842

Anesthesia billing does not use a flat fee per service. Instead, it calculates a total unit count and multiplies that by a dollar-per-unit conversion factor. Medicare and commercial payers both use this approach, though the formula components differ between them.

Many commercial payers, following the ASA Relative Value Guide, use a four-part formula: Total units = Base units + Time units + Physical status units + Qualifying circumstance units, multiplied by the payer’s conversion factor. Medicare uses a shorter formula instead: base units plus time units, multiplied by the locality conversion factor. Physical status modifiers and qualifying circumstance add-on codes must still be reported on every claim, but Medicare assigns them status indicator B, bundled, so they add no separate billable units.

Base units for CPT code 01842

Base units represent the inherent complexity of the anesthesia service for a given procedure. CMS publishes these values annually in its anesthesia base unit file, alongside the AMA’s RVU data. CPT code 01842 carries a base unit value of 6. The table below shows the 018xx family for comparison.

Base unit values are sourced from the CMS anesthesia base unit file and the AMA RVU data set, and should be confirmed annually since values can shift with CPT updates. Always verify against the AMA coding resources or the current CMS fee schedule before submitting claims.

Time units for CPT code 01842

Time units reflect how long the anesthesia service lasts. CMS and most commercial payers calculate one time unit per 15 minutes of anesthesia time, measured from induction to patient recovery handoff. Accurate time documentation is a frequent audit trigger because payers verify start and stop times against the surgical record.

Some payers round to the nearest 15-minute interval; others allow fractional units. Confirm your payer’s rounding policy before billing. Good clinical documentation workflows capture start and stop times at the point of service rather than reconstructing them from the surgical note later.

Modifiers for CPT code 01842

Anesthesia billing modifiers tell the payer who performed the service and under what supervision arrangement. Applying the wrong modifier to CPT code 01842 is a common reason these claims are denied or downcoded. CMS requires one of the following anesthesia billing modifiers on every claim.

Modifier AA requires the anesthesiologist to have been present and personally performing the anesthesia service throughout the case. If the anesthesiologist was concurrently directing other CRNAs, QK applies to the physician’s claim and QX applies to each CRNA’s claim. These must be paired correctly or both claims will be denied. Payer-specific rules may differ from CMS defaults, so always confirm with the patient’s insurer before billing.

Physical status modifiers for CPT code 01842

Physical status modifiers, defined by the ASA, communicate the patient’s overall health complexity. Commercial and ASA-formula billing add these as extra units in the anesthesia calculation, supported by documentation in the anesthesia record. Medicare requires the modifier to be reported on every claim, but assigns physical status add-on units status indicator B, bundled, so they don’t change the Medicare-allowed amount.

Embolectomy patients frequently present as P3 or P4 because acute arterial occlusion often occurs in the context of underlying cardiovascular disease, atrial fibrillation, or recent cardiac events. Documenting the physical status classification in the pre-anesthesia evaluation supports the units billed under an ASA-formula or commercial claim, and Medicare still expects the modifier reported even though it adds no separate payment. Structured pre-procedure documentation also supports the broader compliance requirements medical offices need to meet.

Qualifying circumstances that affect CPT code 01842 billing

Qualifying circumstance add-on codes may be reported alongside CPT code 01842 when specific clinical conditions apply. Under an ASA-formula or commercial claim, they add units to the total. Medicare still requires them reported, but assigns status indicator B, bundled, meaning no separate Medicare payment.

Code 99140 is particularly relevant for CPT code 01842 claims because acute embolism is frequently an emergency. If the procedure was performed under emergency conditions, 99140 may be reported. The anesthesia record must clearly state the emergency nature of the case. Code 99100 applies when the patient is over 70, which is common in the vascular population where arterial emboli are most prevalent. Remember that Medicare bundles both codes into status B, so calculate the Medicare-allowable payment from base and time units alone.

Documentation requirements for CPT code 01842

Complete anesthesia documentation is the most common audit target for CPT code 01842 claims, partly because embolectomy is often performed as an emergency. A missing element in the anesthesia record can trigger a post-payment recoupment even after the claim is paid.

• Anesthesia start and stop times: the exact induction and recovery-handoff times, supporting the number of time units billed.
• Physical status classification and rationale: the pre-anesthesia evaluation documenting the ASA class assigned and the systemic condition that justifies P3 or P4.
• Emergency or qualifying-circumstance evidence: for 99140, the clinical finding confirming an emergency, such as acute limb ischemia, and the decision to proceed without delay; for 99100, the patient’s documented age.
• Provider identification matching the modifier: who performed or directed the service, consistent with AA, QK, QX, QY, or QZ on the claim.
• Diagnosis supporting medical necessity: the ICD-10 code on the claim matching the documented clinical indication.

Vascular surgeons, orthopedic hand surgeons, and interventional radiologists all bill CPT code 01842 for embolectomy anesthesia. Patients often need hand-function rehab afterward, so physical therapy practices frequently pick up the same chart for follow-up care.

Keeping these elements in the same record the clinician completes during the case, rather than reconstructing them afterward, is the most reliable way to avoid a denial or an audit finding.

Medicare reimbursement for CPT code 01842

Medicare reimbursement for CPT code 01842 is calculated as base units plus time units, multiplied by the geographic locality-specific conversion factor published annually by CMS in the Medicare Physician Fee Schedule (MPFS). Physical status modifiers and qualifying circumstance codes must still be reported, but they carry status indicator B, bundled, so they add no additional Medicare-billable units. There is no single national dollar amount for this code, since conversion factors differ by location. The CMS fee schedule tool lets you find the current conversion factor for your locality.

How the anesthesia conversion factor works

The conversion factor is a dollar-per-unit rate. Multiply the total Medicare units, base plus time, by this rate to determine the Medicare-allowable charge. The CY2026 national anesthesia conversion factor is $20.4976 per unit before any geographic adjustment. Always use the locality-specific rate for your billing area.

Medicare worked example for CPT code 01842:

Physical status modifiers and qualifying circumstance codes must still be reported on this claim, but they don’t add units to the Medicare total above.

ASA/commercial-payer worked example (illustrative, not Medicare): some commercial payers price anesthesia using the full four-part formula instead.

The dollar figures above are illustrative only. Actual reimbursement depends on the payer’s conversion factor and the current-year base unit value. Confirm figures against the CMS anesthesia base unit file for Medicare claims, or the ASA Relative Value Guide for ASA-formula and commercial claims, before submitting. Keeping practice billing workflows integrated with current payer schedules narrows the gap between what you charge and what you collect.

Keep CPT code 01842 claims moving with fewer denials

Practice management software like Pabau checks that required insurer fields, such as membership numbers and authorization codes, are complete before a claim can be sent, then gives your billing team a live status view from submission through payment. It does not select the anesthesia modifier or calculate the time units for you. That judgment call still belongs to your billing team.

Book a demo

How CPT code 01842 compares to 01840, 01844, and 01850

Choosing the wrong code from the 018xx family is a common coding error. Each code covers a distinct procedure type at the same anatomical location, and three of the four share the same base units. The table below helps coders select the right code. For the broader arterial code in this family, see CPT code 01840, which covers forearm, wrist, and hand artery work that isn’t embolectomy, shunt, or vein-specific.

Use 01842 only when the operative report confirms the procedure was an embolectomy, clot removal, targeting the forearm, wrist, or hand arteries. If the surgeon inserted or revised a vascular shunt, most often for dialysis access, 01844 is the correct code instead. If the procedure targeted a vein rather than an artery, 01850 applies. Read the operative note before selecting a code from this family.

ICD-10 codes commonly paired with CPT code 01842

Medical necessity for CPT code 01842 has to be supported by an ICD-10 diagnosis code on the claim. Payers check the diagnosis against the procedure to confirm the anesthesia was clinically indicated. Pairing a vague or unrelated diagnosis code with 01842 is a common cause of medical necessity denials.

The codes below are commonly paired with CPT code 01842 for an arterial embolectomy of the forearm, wrist, and hand. Confirm coverage with each payer’s Local Coverage Determination, since acceptable diagnoses can vary.

I74.2 doesn’t subdivide by laterality the way a traumatic injury code would, so the operative note’s description of the affected artery, not a 6th-character choice, carries the clinical detail. A vascular shunt for dialysis access is billed with 01844, not 01842, and it pairs with different diagnosis codes, such as N18.6 (end-stage renal disease) and Z99.2 (dependence on renal dialysis).

Common billing errors and compliance considerations for CPT code 01842

Anesthesia claims involving CPT code 01842 face a predictable set of denial patterns. Most are preventable with accurate documentation and correct modifier pairing. Here are the errors billing specialists see most often with this code.

• Modifier mismatch: Submitting AA when QK/QX applies (or vice versa) is a common denial cause. If an anesthesiologist directed CRNAs while also participating in another case, AA does not apply.
• Time documentation gap: Payers audit start and stop times against the OR schedule. Anesthesia records that lack exact start/stop times or show times inconsistent with the surgical record trigger denials and refund demands.
• Unbundling with the surgical code: Anesthesia codes are not bundled with the surgeon’s CPT code. Each provider bills separately, but coders unfamiliar with the two-claim structure sometimes apply modifier 59 incorrectly.
• Physical status not documented: Billing P3 or P4 additional units on an ASA-formula or commercial claim without a pre-anesthesia assessment documenting the qualifying systemic condition is an audit finding.
• Wrong anatomical code: Billing 01840 (general forearm/wrist/hand arteries) instead of 01842 (embolectomy-specific) undercodes the claim. Billing 01842 when the procedure was a shunt insertion or revision (should be 01844) is an overcoding risk.
• CRNA independent billing without state authorization: CRNA billing under QZ (no medical direction) is only permitted where state law and payer policy allow independent CRNA practice. Billing QZ in an opt-out state without confirming state rules creates compliance exposure.

Practices using claims management software like Pabau’s get a required-field check before a claim can be sent, so missing membership numbers or authorization codes surface before submission rather than after a denial. Confirming the anesthesia modifier and time documentation against the record is still a manual review step. Reviewing HIPAA-compliant billing practices alongside your anesthesia coding protocols also helps protect against audit exposure.

The same documentation discipline carries over to related families elsewhere in the anesthesia section, such as CPT code 01730 for humerus and elbow anesthesia.

Conclusion

CPT code 01842 is straightforward once the anatomy and units are right. Confusing it with 01840, 01844, or 01850 in the same family, or applying the four-part ASA formula to a Medicare claim, are the two most common ways these claims go wrong.

Matching the code to the artery and the exact procedure comes first. Timing anesthesia precisely and applying the correct provider modifier come next. Pairing the claim with a supported ICD-10 code and documenting physical status or emergency circumstances rounds out where most 01842 claims run into trouble.

Pabau checks that the insurer-required fields are complete before a claim can be sent, and gives your billing team a live status view from submission through payment. It does not select the anesthesia modifier or calculate the time units for you, but it catches the missing-field errors that turn a clean claim into a denial. To see how Pabau fits an anesthesia or vascular billing workflow, book a demo with our team.

Continue your research

Billing the venous counterpart in this family? CPT code 01850 covers veins of the forearm, wrist, and hand instead of arteries.

Need the knee and popliteal vein code for comparison? CPT code 01430 applies the same base-plus-time formula to a different body region.

Tracking hand function after a vascular or nerve procedure? The Action Research Arm Test gives a structured way to record upper-limb function during follow-up.

Want documentation captured before billing starts? Patient intake software captures clinical information at the point of care so billing teams have what they need.

Frequently asked questions