PCA CPP common mistakes
PCA CPP · Understand the traps and how to avoid them.
Selecting an ICD-10-CM code from the alphabetic index without verifying it in the tabular list, and coding a diagnosis that the index entry lists as 'see also' or 'code also' at the wrong specificity.
The index is a lookup shortcut and candidates treat its first-listed entry as final, missing the tabular conventions (Excludes1/Excludes2, 'code first', 'use additional code') that change which code is reportable.
What to do instead
Always complete the two-step lookup: find the term in the index, then open the exact code in the tabular list and read every note attached to that code, its category, and its block before assigning it. If the tabular note says another condition must be coded first, sequence accordingly.
Coding a wound repair, lesion excision, or fracture treatment by the wound/lesion/fracture name rather than by the documented depth, size, and site, and choosing the integumentary versus musculoskeletal section incorrectly.
Operative reports use clinical language ('laceration repaired', 'mass removed') that does not state the layer closed or the excised diameter, so candidates default to a familiar-looking code instead of searching by the required measurement and depth.
What to do instead
For each procedure, extract the three data points the code family requires before searching: anatomic site, depth or layer (epidermis/dermis, subcutaneous, fascia, muscle, bone), and size in centimeters including margins. When depth crosses into muscle or bone, search the musculoskeletal section, not integumentary.
Billing an E/M visit at a level supported by a single element (for example, a high-complexity MDM problem) while ignoring the number and complexity of data reviewed and risk, or ignoring total time when time is used to select the level.
Candidates learn one MDM table row well and stop there, or they count chart-review time that the documentation does not support as meeting or exceeding the visit date.
What to do instead
Score all three MDM elements (problems, data, risk) and assign the level of the two elements that meet or exceed the same level; alternatively, when time is the basis, confirm the total time on the date of the encounter is documented and matches the time range for the chosen code. Use one method per encounter, not a mix.
Misapplying modifier 25, 59, or the X{EPSU} modifiers by appending them reflexively to every additional service on the same day instead of documenting and coding a genuinely distinct service.
Modifiers are taught as 'unbundling tools' and candidates use them to force payment rather than to describe separate, identifiable work; they also confuse 59 with XU and XS.
What to do instead
Attach 25 only to an E/M service with a separately identifiable problem above and beyond the procedure; use XS for a separate structure/site, XE for a separate encounter, XP for a separate practitioner, and XU only when the service is distinct and none of the others apply. If the documentation does not describe distinct work, do not append the modifier.
Assigning radiology codes without matching the imaging modality, body region, and whether contrast was used (and whether it was oral, IV, or both), and coding a complete study when only a limited or unilateral study was performed.
Radiology code descriptors are dense and differ by one word ('with' versus 'without' contrast, 'complete' versus 'limited'), and reports often mention contrast in a protocol section far from the impression.
What to do instead
Read the technique and contrast sections of the report explicitly, then match three axes: modality, anatomic region, and contrast status. Distinguish unilateral from bilateral and complete from limited before selecting the code; never default to the complete-study code when the report documents a limited examination.
Coding laboratory and pathology services by the test name on the requisition rather than by the method and specimen, and reporting a panel when the individual tests were ordered and performed separately (or vice versa).
Requisition names ('thyroid panel', 'biopsy') do not map one-to-one to CPT, and candidates do not check whether the performed method (immunoassay, quantitative versus qualitative, flow cytometry) changes the code.
What to do instead
Identify the specimen type, the analytic method, and whether the tests are a defined panel or individually ordered. Code panels only when all components are performed; when only some are performed, code the individual tests. For pathology, separate the professional interpretation from the technical component and confirm which is being billed.
Using a HCPCS Level II code for a supply or drug without verifying units, dosage, and whether the code is per unit, per dose, or per 10 mg, and without checking that the code is current for the date of service.
Drug and supply descriptors embed unit conventions (for example, per 1 mg versus per 10 mg) and HCPCS codes are added, replaced, and discontinued quarterly; candidates memorize a code from study material and apply it without checking the descriptor.
What to do instead
Read the full HCPCS descriptor for the unit basis, calculate units from the documented dose or quantity, and verify the code and its effective date against the current quarter's file before billing. Note discontinued or replaced codes and cross-check the replacement.
Ignoring payer-specific and National Correct Coding Initiative edits, medical necessity policies, and coverage determinations, and coding strictly from the CPT book.
CPT and ICD-10-CM define what can be described, not what is payable; candidates treat code assignment as the whole job and skip the reimbursement rules that determine whether a claim will deny.
What to do instead
Before finalizing a claim, check NCCI procedure-to-procedure and medically unlikely edits, the payer's LCD/NCD or coverage policy for the diagnosis-procedure pair, and the payer's modifier and prior-authorization rules. Document medical necessity in the note, not only on the claim.
Confusing coding-guideline requirements with documentation and compliance requirements, such as reporting a diagnosis the provider did not document, or upcoding a level to match the payer's expectation.
Candidates conflate 'what the code means' with 'what the chart supports' and, under time pressure, code to the reimbursement rather than to the record, which creates false claims exposure.
What to do instead
Code only from documented, authenticated information in the record; if the documentation is ambiguous, query the provider rather than infer. Treat the coding guidelines and the compliance program (internal audits, query policy, code of conduct) as separate checks applied to every chart.
Mishandling anatomy and terminology when a procedure crosses body systems or cavities, such as coding a procedure on the wrong laterality, wrong digit, or wrong vascular family, or misreading terms like 'proximal', 'superficial', and 'ipsilateral'.
Candidates rely on general familiarity with anatomy and do not build a habit of confirming laterality, digit, vessel, and layer from the operative report, where these details are often stated once.
What to do instead
Before selecting any surgical or procedural code, write out the site in full: laterality, specific digit or vessel, anatomic layer, and relationship to adjacent structures. Cross-check against the report's heading, indication, and findings sections so a single mention is not missed.