Go Beyond the TI-RADS Score For Accurate Thyroid Ultrasound Coding
Learn how to report single and multiple nodules. Thyroid ultrasound reports routinely describe nodules using the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS). These reports may include numerical scores, risk categories, and recommendations for surveillance or fine-needle aspiration (FNA). Although these details are clinically important, they can create confusion when assigning diagnosis codes. For radiology coders, the distinction is straightforward: TI-RADS describes imaging-based suspicion for malignancy; it does not establish a histologic diagnosis. Accurate coding requires understanding the purpose of TI-RADS, identifying the confirmed imaging findings, and applying ICD-10-CM guidelines without overstating the diagnosis. Understand ACR TI-RADS The ACR introduced TI-RADS in 2017 to standardize thyroid nodule reporting and help clinicians determine which nodules warrant biopsy or continued ultrasound surveillance. The system assigns points based on five sonographic characteristics: composition, echogenicity, shape, margins, and echogenic foci. Features associated with greater suspicion for malignancy receive higher point values. The combined score places the nodule into one of five categories: Category Points Classification TR1 0 Benign TR2 2 Not suspicious TR3 3 Mildly suspicious TR4 4-6 Moderately suspicious TR5 7 or more Highly suspicious The ACR combines these categories with nodule size to establish management recommendations. For example, a TR3 nodule generally meets the FNA threshold at 2.5 cm, whereas a TR4 nodule meets the threshold at 1.5 cm and a TR5 nodule at 1.0 cm. Smaller nodules may warrant surveillance depending on their classification and size. These thresholds are clinical management recommendations, not coding criteria. Even a TR5 classification does not confirm thyroid malignancy. Similarly, a TR1 classification does not automatically establish a pathologically proven benign neoplasm. The TI-RADS designation does not change the ICD-10-CM diagnosis assigned to a thyroid nodule. Report the Diagnostic Ultrasound Code 76536 (Ultrasound, soft tissues of head and neck (eg, thyroid, parathyroid, parotid), real time with image documentation) is the CPT® code for a diagnostic thyroid ultrasound. This code describes diagnostic ultrasound evaluation of the head and neck soft tissues, including the thyroid gland. Report 76536 once for the examination rather than for each individual nodule identified. Multiple nodules, bilateral thyroid findings, or multiple TI-RADS classifications do not justify additional units of 76536 for the same examination. The report should support the diagnostic study performed, including its relevant findings and imaging documentation. Nodule characteristics, measurements, and follow-up recommendations contribute to a complete interpretation but do not change the CPT® code. The same CPT® code applies when the radiologist performs the thyroid ultrasound for a palpable abnormality, a nodule incidentally identified on another imaging study, or surveillance of a previously identified nodule. Code the Finding, Not the Risk Score The ICD-10-CM Alphabetic Index and Tabular List determine code assignment; the TI-RADS scoring system does not. Commonly applicable codes include the following: Code E04.1: This code applies to a documented thyroid nodule when supported by the diagnostic findings. The ICD-10-CM Alphabetic Index directs thyroid nodule to E04.1, and the Tabular List includes colloid nodules and thyroid cystic nodules not otherwise specified (NOS). The term “nontoxic” in the code descriptor should not be interpreted as requiring laboratory confirmation of normal thyroid function when the Alphabetic Index directs an otherwise unspecified thyroid nodule to E04.1. Code E04.2: Use this code when the report establishes multinodular goiter. It represents the documented condition rather than requiring a separate diagnosis code for each nodule. Code E04.9: This code describes a documented goiter when its type is not further specified. It should not replace the more specific nodule or multinodular goiter codes when the documentation supports them. Other thyroid disorders, including toxic nodules, thyroiditis, and malignancy have separate coding pathways when the provider establishes those diagnoses. Know Why TI-RADS Does Not Support Neoplasm Coding The most consequential coding error occurs when radiologic suspicion is translated into an unconfirmed neoplasm diagnosis. Consider a report stating: “1.8 cm solid hypoechoic right thyroid nodule with punctate echogenic foci, TR5. Ultrasound-guided FNA recommended.” The finding establishes a thyroid nodule with highly suspicious sonographic characteristics, but it does not establish thyroid cancer. You reach for the neoplasm table only when a provider documents a neoplasm and its behavior. Chapter 4 of the ICD-10-CM code book also notes that all neoplasms are classified in Chapter 2, which is why a nodule is not a neoplasm by default. When the report documents a single nontoxic thyroid nodule, E04.1 is appropriate. The TR5 designation does not independently support assigning any of the following codes: These codes require documentation supporting their respective diagnoses. A neoplasm of uncertain behavior is not synonymous with a suspicious imaging finding or an uncertain clinical diagnosis. The 2027 ICD-10-CM Official Guidelines, Section IV.H, prohibit coding outpatient diagnoses documented as “probable,” “suspected,” “questionable,” or similar terms indicating uncertainty. Furthermore, Section IV.K instructs coders to use confirmed or definitive diagnoses documented in the interpreting physician’s final diagnostic report when available. Therefore, when the physician definitively identifies a thyroid nodule, you code the nodule, not the possibility that the nodule could represent malignancy. Correctly Code Single Nodules, Multiple Nodules, and Incidental Findings The clinical indication and final interpretation should be reviewed together. Review these different coding scenarios: Code the confirmed thyroid nodule with E04.1 rather than assigning an unspecified abnormal imaging finding code simply because the nodule was originally discovered incidentally. If the ultrasound does not establish a definitive diagnosis, select the appropriate documented sign, symptom, or abnormal finding under applicable outpatient coding guidelines. Remember the Focus of Surveillance Ultrasounds TI-RADS recommendations frequently generate surveillance examinations to assess nodule growth or changes in sonographic appearance. You will continue to report a follow-up ultrasound with 76536 when the radiologist performs and documents a diagnostic examination. For example, a radiologist reassesses a previously identified TR4 thyroid nodule after one year. The report confirms a stable 1.2 cm nodule and recommends additional surveillance. The appropriate diagnosis remains the established thyroid nodule. Stability does not eliminate the diagnosis, and the continued TR4 classification does not establish neoplastic disease. Likewise, an increase from TR3 to TR4 or TR5 may change clinical management but does not independently establish a new ICD-10-CM disease category. You should also avoid automatically assigning Z09 (Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm) for surveillance of a nodule that remains present. Follow-up examination codes generally describe surveillance after completed treatment of a condition that no longer exists rather than ongoing evaluation of an active thyroid nodule. Identify When Ultrasound-Guided FNA Enters the Picture Some thyroid nodules subsequently undergo ultrasound-guided FNA for cytologic evaluation. The applicable CPT® codes include the following: Note: Code 60100 reports percutaneous core needle biopsy of the thyroid. Guidance is not included, so you may assign 76942 (Ultrasonic guidance for needle placement (eg, biopsy, aspiration, injection, localization device), imaging supervision and interpretation) for ultrasound guidance in addition to 60100, when applicable. A distinction must also be made between diagnostic ultrasound and imaging performed solely for biopsy guidance. Routine ultrasound localization or evaluation necessary to guide the FNA does not automatically support separate reporting of 76536. Reporting an additional diagnostic ultrasound requires a separately supported service consistent with CPT® instructions, medical necessity, and applicable National Correct Coding Initiative (NCCI) edits. Importantly, the decision to perform an FNA does not establish malignancy. The diagnosis assigned to the biopsy encounter must reflect the documented condition and available diagnostic information. If cytology subsequently establishes a definitive diagnosis, the coding for subsequent services should reflect the confirmed findings. You shouldn’t automatically translate suspicious or indeterminate cytology into a malignant neoplasm code or a neoplasm of uncertain behavior code without supporting diagnostic documentation. The result does not reach back to the ultrasound claim. The diagnosis for the 76536 encounter is what the radiologist documented in that report, so do not go back and revise the ultrasound claim to a neoplasm code because a later cytology result came back abnormal. Conclusion ACR TI-RADS provides valuable information about thyroid nodule characteristics, malignancy risk, and recommended clinical management. However, its categories should never be mistaken for histologic diagnoses. TI-RADS answers “What should we do with this nodule?” not “What is it?” For accurate thyroid ultrasound coding, identify the diagnostic service performed, review the radiologist’s definitive impression, distinguish a thyroid nodule from a documented multinodular goiter, and apply ICD-10-CM outpatient coding guidelines. Laura Manser, CPC, CPMA, CEMC, CDEO, CIRCC, CPCO, RCC, Director of Provider
Education and Compliance Officer, PBS Radiology Business Experts, Reno, Nevada
