ICD-10 Code F99: Mental disorder, not otherwise specified
ICD-10 Code F99: Definition and billable status ICD-10 Code F99 represents “Mental disorder, not otherwise specified.” It is a billable/specific ICD-10-CM code valid for reimbursement submission. The 2026 edition became effective on October 1, 2025, per the annual ICD-10-CM update issued by CMS and the CDC’s National Center for Health Statistics (NCHS). F99 sits at […]
ICD-10 Code F69: Adult Personality Disorder Guide
Most personality disorder diagnoses resolve to a specific ICD-10-CM code. F69 exists for the cases that don’t. When clinical documentation confirms a disorder of adult personality and behavior but the evidence doesn’t support a more precise classification, this billable code keeps the claim moving without forcing a diagnosis the record can’t support. That said, F69 […]
ICD-10 Code F09: Unspecified mental disorder guide
ICD-10 Code F09 is a billable ICD-10-CM code for unspecified mental disorder due to a known physiological condition. It sits at the end of the organic mental disorder block, reserved for cases where a physiological cause is confirmed but the presentation doesn’t fit any more specific code from F01 through F06. This guide covers F09’s […]
ICD-10 code K12.2: Cellulitis and abscess of mouth
A cellulitis or abscess on the floor of the mouth can escalate from a swollen, painful jaw to a life-threatening airway emergency within hours. How that infection is documented and coded shapes everything that follows, from the claim to the clinical record. That’s where ICD-10 code K12.2 comes in, the ICD-10-CM diagnosis for cellulitis and […]
ICD-10 Code M65.4: Radial styloid tenosynovitis (de Quervain’s)
Wrist pain on the thumb side is one of the most common musculoskeletal complaints seen in hand surgery, orthopaedic, physical therapy, and primary care settings. Yet de Quervain’s tenosynovitis is also one of the most frequently miscoded conditions. Miscoding happens mostly when laterality is left unspecified or when clinical documentation doesn’t explicitly support the diagnosis. […]
ICD-10 code J36: Peritonsillar abscess coding guide
ICD-10 code J36: Definition and billable status A patient walks in with a one-sided sore throat, a muffled voice, and a jaw too tight to open all the way. That’s peritonsillar abscess, and on the claim, it’s ICD-10 code J36. J36 is easy to confuse with acute tonsillitis (J03.-), since the two look alike on […]
ICD-10 code I81: Portal vein thrombosis diagnosis and coding guide
ICD-10 Code I81 is a billable ICD-10-CM diagnosis code for portal vein thrombosis (PVT), a blood clot in the portal vein, the vessel that carries blood from the gastrointestinal tract, spleen, and pancreas to the liver. It’s frequently confused with K75.1, which classifies a related but distinct condition, phlebitis of the portal vein, under the […]
ICD-10 Code C54.1: Malignant neoplasm of endometrium
ICD-10 Code C54.1 is the billable, site-specific diagnostic code for malignant neoplasm of the endometrium, the inner lining of the uterine corpus. Endometrial cancer is the most common gynecologic malignancy in the United States. Using the unspecified uterine code C55 when the chart documents endometrial involvement is one of the most frequently flagged errors in […]
ICD-10 Code C41.3: Malignant neoplasm of ribs, sternum and clavicle
Most bone malignancy coding errors happen before the claim ever reaches the payer. A coder selects C41.3 for a patient with metastatic lung cancer that has spread to the ribs, the claim denies, and the audit trail reveals the wrong primary designation. ICD-10 Code C41.3 is the correct code only when the ribs, sternum, or […]
ICD-10 Code C68.0: Malignant neoplasm of urethra
ICD-10 Code C68.0 is the billable ICD-10-CM diagnosis code for malignant neoplasm of the urethra, used once pathology and physician documentation confirm the urethra as the primary tumor site. Urethral malignancies account for less than 1% of all urologic cancers, but coders still encounter C68.0 regularly in oncology, urology, and general surgery settings. Misassigning the […]