Presented below is an analysis of new and ongoing initiatives under the Office of the Inspector General (OIG) Work Plan [1] and the Centers for Medicare & Medicaid Services (CMS) approved Recovery Audit Contractor (RAC) reviews [2] as of January 2025. The focus is on outpatient initiatives related to HIM coding and documentation requirements and is not intended to review every active work plan item. For each relevant initiative, a summary of the OIG or RAC compliance concern, the month and year published and added to the plan, and related coding and documentation requirements is included below. More importantly, for each outpatient initiative presented, UASI has included specific suggested compliance activities to assist our clients with their ongoing compliance efforts. The information below includes an analysis of the following active outpatient topics: · Medicare Payments for Lower Extremity Peripheral Vascular Procedures (OIG) · Medicare Part C Audits of Documentation Supporting Specific Diagnosis Codes (OIG) · Audits of Medicare Part C Health Risk Assessment Diagnosis Codes (OIG) · Minimally Invasive Surgical (MIS) Fusion of the Sacroiliac Joint (RAC) · Transurethral Waterjet Ablation of the Prostate for Benign Prostatic Hyperplasia (BPH) with Lower Urinary Tract Symptoms (LUTS) (RAC) · Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea (RAC) Medicare Payments for Lower Extremity Peripheral Vascular Procedures, June 2024 Minimally invasive procedures aiming to improve blood flow when arteries narrow or become blocked because of peripheral arterial disease have been identified by CMS and whistleblower fraud investigations as vulnerable to improper payments. OIG will analyze Medicare fee-for-service for peripheral vascular procedures for questionable characteristics and review the program integrity activities of CMS and its contractors to combat fraud, waste, and abuse specific to these procedures. Additionally, these procedures will be assessed to ensure compliance with CMS requirements and meet applicable treatment guidelines. Documentation should include: · A description of the studies performed, and any contrast media and/or radiopharmaceuticals used · Any patient adverse reactions and/or complications · Normal and abnormal findings and comparison with prior relevant studies · Variations from normal should be documented along with measurements. · The report should address or answer any specific clinical questions. · Results of all testing must be shared with the referring physician · Adequate documentation to support medical necessity of performing non-invasive vascular studies · medically necessary follow-up noninvasive vascular studies post-angioplasty is dictated by the vascular distribution treated CMS expects that non-invasive vascular studies are not performed more than once a year. A complete review of billing and coding requirements, including the CPT codes and an extensive list of ICD-10-CM codes that support medical necessity can be found at Article - Billing and Coding: Non-Invasive Peripheral Arterial Vascular Studies (A57593) (cms.gov) Medicare Part C Audits of Documentation Supporting Specific Diagnosis Codes, November 2023 This is the first of two workplan items focusing on high-risk diagnoses that might result in inaccurate risk adjusted data. The first item focuses on quality of the documentation supporting the diagnoses and the second item: Nationwide Audits of Medicare Part C High-Risk Diagnosis Codes focuses on code accuracy, Payments to Medicare Advantage (MA) organizations are risk-adjusted based on each enrollee's health. Inaccurate diagnoses may cause CMS to pay MA organizations improper amounts. In general, MA organizations receive higher payments for enrollees with more complex diagnoses. CMS estimates that 9.5 percent of payments to MA organizations are improper, mainly due to unsupported diagnoses submitted by MA organizations. Prior OIG reviews have shown that some diagnoses are more at risk than others to be unsupported by medical record documentation. We will perform a targeted review of these diagnoses and will review the medical record documentation to ensure that it supports the diagnoses that MA organizations submitted to CMS for use in CMS's risk score calculations and to determine whether the diagnoses submitted complied with Federal requirements. Nationwide Audits of Medicare Part C High-Risk Diagnosis Codes, November 2023 Medicare Advantage (MA) organizations receive risk-adjusted reimbursement based on the health status of each enrollee. All MA organizations submit risk-adjustment data to CMS according to defined regulations. Mis-coded diagnoses can result in incorrect payments back to MA organizations. These audits will focus on identified high risk diagnoses being mis-coded and resulting in increased risk-adjusted payments from CMS. In a previous CMS audit of high-risk diagnoses, 183 of the 280 sampled enrollee-years, resulted in the following findings: 1) the medical record(s) provided did not support the diagnosis code(s) or 2) the medical record(s) could not be located; therefore, the diagnosis code(s) was not validated. [3] Through data mining techniques and meetings with medical professionals, CMS identified diagnoses that are at a higher risk of being miscoded. These diagnoses include: · Major depressive disorder: Concerns related to this diagnosis note that the diagnosis was documented but the patient did not have an antidepressant medication prescribed. As such, a major depressive disorder may not be supported in the documentation. · Acute stroke: Findings for this diagnosis noted that an acute stroke diagnosis on a physician claim during a service year does not correspond to an inpatient or outpatient hospital claim. · Vascular claudication: The vascular claudication findings noted a diagnosis during the service year which was not present during the preceding 2 years. · Cancer: Findings related to several cancer diagnoses in this audit were related to a cancer diagnosis during the service year, however no treatment (e.g., surgery, radiation, or chemotherapy) was found within a 6-month period before or after the diagnosis. A diagnosis of history of cancer may be more appropriate. These cancer diagnoses include: o Breast cancer o Colon cancer o Prostate cancer o Lung cancer · Acute myocardial infarction (AMI): These specific findings noted diagnoses of acute myocardial infarction on a physician or outpatient claim during the service year. However, there was not an AMI diagnosis on a corresponding hospital claim. A code for the history of MI may be more appropriate. · Embolism: Enrollees received a diagnosis of acute or chronic embolism without an anticoagulant medication, which is typically used to treat an embolism. The history of embolism diagnosis may be more appropriate. These findings confirm the CMS intention to continue auditing for and enforcing complete and accurate clinical documentation. UASI Suggested Compliance Activities for this Initiative 1. Improve population health data analytical capabilities and monitor high risk diagnosis reporting. 2. Utilize reports to determine the frequency of these high-risk diagnoses associated with risk-adjustment enrollees. Minimally Invasive Surgical (MIS) Fusion of the Sacroiliac Joint, June 2023 Documentation will be reviewed to determine whether minimally invasive surgical fusion of the sacroiliac joint met Medicare coverage criteria and was reasonable and necessary. The only code included in this review is CPT code 27279, Arthrodesis, sacroiliac joint, percutaneous or minimally invasive (indirect visualization), with image guidance, includes obtaining bone graft when performed, and placement of transfixing device. Additional procedure coding information can be found in the CPT Assistant, April 2023, Volume 33, Issue 4, page 16. There are multiple different ICD-10-CM diagnosis codes that support the medical necessity for this procedure. ICD-10-CM Diagnosis Code Code Description M43.27 Fusion of spin, lumbosacral region M43.28 Fusion of spin, sacral and sacrococcygeal region M46.1 Sacroiliitis, NEC M51.17 Intervertebral disc disorders with radiculopathy, lumbosacral region M53.2X7 Spinal instabilities, lumbosacral region M53.2X8 Spinal instabilities, sacral and sacrococcygeal region M53.3 Sacrococcygeal disorders, NEC M533.87 Other specified dorsopathies, lumbosacral region M53.88 Other specifies dorsopathies, sacral and sacrococcygeal region M99.14 Subluxation complex (vertebral) of sacral region S33.2XXA Dislocation of sacroiliac and sacrococcygeal joint, initial encounter S33.2XXD Dislocation of sacroiliac and sacrococcygeal joint, subsequent encounter S33.2XXS Dislocation of sacroiliac and sacrococcygeal joint, sequela S33.6XXA Sprain of sacroiliac joint, initial encounter S33.6XXD Sprain of sacroiliac joint, subsequent encounter S33.6XXS Sprain of sacroiliac joint, sequela S33.8XXA Sprain of other parts of lumbar spine and pelvis, initial encounter S33.8XXD Sprain of other parts of lumbar spine and pelvis, subsequent encounter S33.8XXS Sprain of other parts of lumbar spine and pelvis, sequela Coverage Indicators [4] This procedure is considered medically necessary when ALL the following criteria are met: · Have moderate to severe pain with functional impairment and pain persists despite a minimum six months of intensive nonoperative treatment that must include medication optimization, activity modification, bracing, and active therapeutic exercise targeted at the lumbar spine, pelvis, SIJ, and hip including a home exercise program · Patient’s report of typically unilateral pain that is caudal to the lumbar spine (L5 vertebrae), localized over the posterior SIIJ, and consistent with SIJ pain · A thorough physical examination demonstrating localized tenderness with palpation over the sacral sulcus in the absence of tenderness of similar severity elsewhere and that other obvious sources for their pain do not exist · Positive response to a cluster of 3 provocative tests · Absence of generalized pain behavior · Diagnostic imaging studies that include ALL the following o Imaging (plain radiographs and a CT or MRI) of the SI joint that excludes the presence of destructive lesions, fracture, traumatic SIJ instability, or inflammatory arthropathy that would not be properly addressed by percutaneous SIJ fusion. o Imaging of the pelvis (AP plain radiography UASI Suggested Compliance Activity for this Initiative 1. Utilize reports to determine the frequency of CPT code 27279. 2. Based on these findings, determine the need to audit a percentage of the total cases. Transurethral Waterjet Ablation of the Prostate for Benign Prostatic Hyperplasia (BPH) with Lower Urinary Tract Symptoms (LUTS), April 2023

Definition Pressure ulcers are localized damage to the skin and/or soft tissue caused by prolonged pressure, often associated with immobility and/or lack of sensation. Contributing factors can include moisture and nutritional deficiencies. Diagnostics Stages and Definitions (NPIAP; www.npiap.com ): Stage 2: Partial-thickness skin loss with exposed dermis. The wound bed is viable, pink or red, moist, and may present as an intact or ruptured serum-filled blister. Stage 3: Full-thickness skin loss. Adipose tissue is visible in the ulcer, with granulation tissue and epibole (rolled wound edges) often present. Slough and/or eschar may be visible. Stage 4: Full-thickness skin and tissue loss with exposed or directly palpable fascia, muscle, tendon, ligament, cartilage, or bone. Slough and/or eschar may be present. Unstageable: Obscured full-thickness skin and tissue loss where the extent of tissue damage cannot be confirmed due to slough or eschar. Removal may reveal a Stage 3 or Stage 4 injury. Treatment Wound care/dressings, debridement, wound care referral, hyperbaric oxygen therapy Pain management, antibiotics, topical treatments Advanced stage treatment may include necrotic tissue excision, wet-to-dry saline or hypochlorite solution dressings, topical antibiotics, or specialized gels Background The term "pressure ulcer" is outdated. The National Pressure Ulcer Advisory Panel (NPIAP), founded in 1987, changed its terminology to "pressure injury" in 2016 and updated its name in 2019. A pressure injury is now defined as localized skin and soft tissue damage typically found over a bony prominence or caused by medical devices. Statistics on pressure injuries are limited. The 1999 Fifth National Pressure Prevalence Survey reported a 14.8% prevalence in acute care hospitals, with 7.1% occurring during hospital stays. Increased Risk Factors: Neurologic disease, cardiovascular disease, prolonged anesthesia, dehydration, malnutrition, hypotension, and surgery. ICD-10 Codes and HCC Mapping: HCC 379: Community, Non-Dual, Aged - 1.965 HCC 381: Community, Non-Dual, Aged - 1.075 HCC 382: Community, Non-Dual, Aged - 0.838 Coding and CDI Tips Document the pressure ulcer's location and its stage Note treatment and any complications related to the ulcer Indicate if there was a referral to wound care Clarify that pressure injuries are coded as pressure ulcers Differentiate pressure ulcers from moisture-associated skin damage (MASD) Specify ulcer stage, including unstageable ulcers, to ensure accurate HCC assignment For ulcers described as "healing," assign the code for the current stage. If "healed," no code is necessary Distinguish between pressure and chronic non-pressure ulcers , which map to different HCCs (380, 383) Query Example Visit note from [date] indicates the presence of a pressure ulcer on the right heel. The stage is not documented. Exam on [date] describes full-thickness ulceration into subcutaneous soft tissue. Please specify the stage of the pressure ulcer: Stage 2 Other stage (please specify)  References Centers for Medicare and Medicaid. (2023). Announcement of Calendar Year (CY) 2024 Medicare Advantage (MA) Capitation Rates and Part C and Part D Payment Policies. CMS Edsberg, L. E., et al. (2016). Revised National Pressure Ulcer Advisory Panel Pressure Injury Staging System. J Wound Ostomy Continence Nurs, 43(6), 585-597. doi:10.1097/won.0000000000000281 Tang, C., Pinson, R. (2024). CDI Pocket Guide by Pinson and Tang. CDI Plus Zaidi SRH, Sharma S. (2024). Pressure Ulcer. In StatPearls [Internet]. NCBI

Obesity: Understanding the Condition and Its Implications Definition: • Obesity: A state of excess storage of body fat. • Overweight: Refers to excess body weight for height. Facts and Statistics: The Centers for Disease Control (CDC) reported in August 2024 that more than 100 million U.S. adults aged 20 or older have obesity, with 22 million classified as severely obese. Additionally, 14.7 million cases of obesity have been reported in U.S. children and adolescents aged 2-19. The National Center for Health Statistics shows that the obesity prevalence in adults (aged 20 and older) rose from 19.4% in 1997 to 31.4% by the reporting period of January-September 2017. Diagnostic Criteria: • Underweight: BMI < 18.5 kg/m² • Normal Weight: BMI 18.5–24.9 kg/m² • Overweight: BMI 25–29.9 kg/m² • Obesity (Class 1): BMI 30–34.9 kg/m² • Obesity (Class 2): BMI 35–39.9 kg/m² • Extreme Obesity (Class 3): BMI > 40 kg/m² Note: Morbid obesity is defined by a BMI > 40 kg/m², or a BMI of 35 or higher with at least one weight-related comorbidity, such as diabetes, heart disease, stroke, hypertension, or arthritis. Diagnostic Tests: • Fasting Lipid Panel • Liver Function Studies • Thyroid Function Tests • Fasting Glucose and Hemoglobin A1c (HbA1c) Treatment: • Nutritional consult • Counseling on diet and exercise • Medications such as GLP-1s • Bariatric surgery procedures • Treatment for associated comorbid conditions ________________________________________ Coding and CDI Considerations: • Overweight and obesity codes are found in category E66. An instructional note directs the reporting of BMI, if known, as an additional diagnosis (adults: Z68.1-Z68.45; pediatrics: Z68.5-). • Code E66.01 classifies morbid (severe) obesity due to excess calories. Documentation of "severe" obesity allows the assignment of this code. However, E66.01 has an Excludes1 note that it should not be coded with E66.2, which refers to morbid obesity with alveolar hypoventilation. • BMI codes can be taken from non-physician documentation, but the physician must provide an associated diagnosis. IPPS FY 2025 New Codes for Obesity: • E66.811 Obesity, Class 1 • E66.812 Obesity, Class 2 • E66.813 Obesity, Class 3 (synonymous with morbid obesity) • E66.89 Other obesity, not elsewhere classified Current coding guidance states that obesity and morbid obesity are always clinically significant and should be reported when documented. No additional documentation is required to support clinical significance for this condition (such as evaluation, treatment, or increased monitoring). Obesity and Comorbid Conditions: CDI specialists should review for obesity-related comorbid conditions, such as: • Obstructive sleep apnea (OSA) • Malignancy • Coronary artery disease (CAD) • Hypertension (HTN) • Gallbladder disease • Osteoarthritis • Diabetes • Stroke • Depression If the patient's BMI is 35 or higher and they have a comorbid condition related to obesity, this may be considered morbid obesity. The provider should document the relationship between weight and the comorbid condition to demonstrate the need for specific management and strengthen medical necessity and decision-making. Obesity also impacts risk adjustment methodologies, including Elixhauser and AHRQ PSIs. Query Example: Please specify if the condition you are managing can be represented as: • Morbid Obesity • Obesity, Class 2 • Other condition (please specify) The following clinical indicators are noted in documentation: • RN admission assessment with BMI 38.5 • Nutrition consult ordered • Chronic conditions of Type II Diabetes and Hypertension References: • AHA Coding Clinic 2018 Fourth Quarter, p. 77 • Hamdy, O. (2024). Obesity. Medscape. www.medscape.com • Official Coding Guidelines Sections I.C.19.a and I.C.19.c • Pinson, R., Tang, C. (2024). Body Mass Index and Obesity. CDI Pocket Guide. CDIPlus • Prescott, L., Manz, (2024). Morbid Obesity. ACDIS Pro • US Centers for Disease Control and Prevention. New CDC Data Show Adult Obesity Prevalence Remains High. CDC. Available at https://www.cdc.gov/media/releases/2024/p0912-adult-obesity.html . September 12, 2024; Accessed: November 26, 2024.

Critical Illness Myopathy (CIM): Describes a rapidly evolving primary myopathy with generalized muscle wasting due to prolonged immobilization. Characterized by more proximal than distal weakness, sensory preservation, and atrophy depending on the duration of illness. Usually occurs in the intensive care setting. Providers may also refer to this as acquired care weakness when no specific etiology is identified. Critical Illness Polyneuropathy (CIP): Exhibits both sensory and motor manifestations, determined by physical exam and electrodiagnostic study. Characterized by more distal than proximal weakness, sensory changes, and limited atrophy. Critical Illness Polyneuromyopathy (CIPNM): Describes a combined myopathy with characteristics of both CIM and CIP. Characterized by a combination of proximal greater than distal weakness, distal sensory loss, and variable atrophy. Clinically, CIM and CIP manifest as limb and respiratory muscle weakness. Risk Factors for CIM Prolonged intubation/failure to wean Gram-negative bacteremia, hyperglycemia, hyperpyrexia, hyperosmolarity, hypoalbuminemia, hypoxia, hypotension, hyper/hypocalcemia Advanced age or female sex Sepsis, ARDS, COVID-19, asthma, organ transplant patients Use of steroids and/or non-depolarizing neuromuscular blockades (atracurium besylate, vecuronium bromide, pancuronium bromide) Diagnostic Criteria Electrodiagnostic studies: Nerve conduction studies, electromyography, and direct muscle stimulation Past medical history evaluation Clinical exam Medical Research Council (MRC) sum score: Used as an initial diagnostic measure of muscle strength in conscious patients (CIP and CIM are thought to be present if the score is less than 48) Diagnostic labs to rule out other conditions contributing to weakness Muscle biopsy: Usually necessary to firmly establish the diagnosis of CIM Provider documentation should clearly differentiate between critical illness myopathy and critical illness polyneuropathy to capture accurate code assignment. Example Scenario: A patient admitted to the ICU for sepsis with ARDS secondary to COVID-19 pneumonia has a prolonged recovery due to difficulty weaning off the ventilator. The provider documents critical illness neuropathy. Assign the principal diagnosis code for sepsis with secondary diagnosis codes for ARDS, COVID-19 pneumonia, and critical illness polyneuropathy (G62.81). A query could be considered for critical illness myopathy (G72.81) to add an additional CC if sufficient clinical indicators are present. Each code impacts risk adjustment methodologies differently. Additional Tips Critical illness myopathy is underrecognized because it has a clinical appearance that is similar to critical illness polyneuropathy. There are no identified treatment protocols other than preventative and supportive measures, with a primary focus on rehabilitation and mobilization of the patient. CIM/CIP affects over a third of severely critically ill patients and more than a quarter of those requiring ventilatory assist for at least seven days. Almost 100% of patients who demonstrate multiple organ failure experience CIM/CIP. Record reviews should consider the presence of immobility-related complications such as DVT, pressure injuries, and aspiration pneumonia. CIM and CIP can also be seen in other hospital settings and can manifest in patients with a severe illness that complicates care.  References: American Hospital Association. (2024). Coding Handbook, Disease of the Nervous System and Sense Organs; Critical Illness Myopathy. Gutmann, L., & Gutmann, L. (1999, May). Critical Illness Neuropathy and Myopathy. JAMA Neurology. Retrieved from: Critical Illness Neuropathy and Myopathy | Critical Care Medicine | JAMA Neurology | JAMA Network Prescott, L. & Manz, J. (2023). 2024 ACDIS Pocket Guide. The Essential CDI Resource (pp. 123-127). HCPro. Shepherd, S., Batra, A., & Lerner, D. (2023, August). Review of Critical Illness Myopathy and Neuropathy. NIH. National Library of Medicine. National Center for Biotechnology Information. Retrieved from: Review of Critical Illness Myopathy and Neuropathy - PMC (nih.gov)

Transient Tachypnea of the Newborn (TTN) TTN : a parenchymal lung disorder characterized by pulmonary edema resulting from delayed resorption and clearance of fetal alveolar fluid. It is the most common cause of respiratory distress in late preterm and term infants and is generally a benign, self-limited condition. Clinical Manifestations of TTN · Onset usually between the time of birth and two hours after delivery · Tachypnea – most common feature with respiratory rate > 60 breaths per minute · Infants with more severe disease may exhibit: Cyanosis Increased work of breathing which includes: Nasal flaring Mild intercostal and subcostal retractions Expiratory grunting · Anterior-posterior diameter of the chest may be increased · Typically with clear lungs (no rales/rhonchi) · Mild to moderate TTN are symptomatic for 12-24 hours but signs may persist as long as 72 hours in more severe cases · Characteristic radiographic features: o CXR – increased lung volumes with flat diaphragms, mild cardiomegaly, prominent vascular markings in a sunburst pattern originating at the hilum, fluid in the interlobar fissures, pleural effusions, alveolar edema appearing as fluffy densities. There are no areas of alveolar densities or consolidation o Lung US – pulmonary edema, compact B lines, double lung point, regular pleural line without consolidation TTN is a benign disorder and pathologic conditions that also present with respiratory distress must be excluded. Pneumonia – chest radiography differentiates PNA from TTN as neonatal PNA is characterized by alveolar densities with air bronchograms or patchy infiltrates, not seen in TTN. Sepsis – infants with sepsis and respiratory distress are differentiated from those with TTN with the persistence of additional symptoms and the lack of the characteristic chest radiographic findings of TTN. Congenital cardiac disease - TTN is distinguished from congenital heart disease by physical findings (e.g., heart murmur, abnormal precordial activity), chest radiography, pre- and post-ductal pulse oximetry, and echocardiography. Respiratory distress syndrome – differentiated from TTN with a characteristic chest radiograph of a ground glass appearance with air bronchograms. Caused by surfactant deficiency most common in very preterm infants. Code for Transient tachypnea of newborn (TTN) falls under ICD-10 Chapter 16 – Certain conditions originating in the perinatal period [P00-P96] · P19-P29 – Respiratory and cardiovascular disorders specific to the perinatal period · P22 - Respiratory distress of newborn · P22.0 – Respiratory distress syndrome of newborn · P22.1 – Transient tachypnea of newborn · P22.8 – Other respiratory distress of newborn · P22.9 – Respiratory distress of newborn, unspecified Additional Tips: · TTN is also documented as Respiratory distress syndrome Type II, Wet lung syndrome · Tachypnea alone is just a symptom · Most common risk factors for TTN include prematurity, Cesarean delivery, maternal diabetes, maternal obesity, maternal asthma · Infants with TTN rarely require a fraction of inspired oxygen (FiO2) >0.4. References Johnson, K. E. (2021, August 30). Transient tachypnea of the newborn. UpToDate. www.uptodate.com/contents/transient-tachypnea-of-the-newborn “Respiratory Conditions Neonatal.” Pro ACDIS Pocket Resource Online, pro.acdis.org/inpatient/conditions/respiratory-conditions-neonatal. Accessed 4 Dec. 2023.

This is a short synopsis of a possible patient record and is not intended to be all-inclusive. This is for educational purposes only and not intended to replace your institutional guidelines.

Common definitions for this discussion: Adverse Effect: occurs when a substance is taken according to direction and a reaction occurs Poisoning: indicates improper use of medication including combination with alcohol, overdose, wrong drug, wrong dose, or taken in error Underdosing refers to taking less or discontinuing a medication that is prescribed Toxic Effects: a reaction, consequence, or effect of a non-medicinal substance such as alcohol, animal venom, or carbon monoxide Provider documentation needs to be clear whether a drug was taken as directed or improperly administered to determine an adverse effect vs. poisoning. For example, a patient with a GI bleed due to Coumadin therapy would need clarification if the Coumadin was taken properly or not taken properly. Taken properly as directed would have an adverse effect – Principal diagnosis is the nature of the adverse effect. GI bleed is associated with Coumadin therapy, taken properly. Taken improperly would be poisoning – The principal diagnosis is the poisoning effect from improper coumadin. GI bleeding is associated with Coumadin therapy, not taken properly Provider documentation should be clear whether a diagnosis results from a cause/effect of poisoning. For example, a patient admitted/discharged with a diagnosis of musculoskeletal chest pain with cocaine use just before the onset of symptoms. Chest pain associated with cocaine use provides clarity on the etiology of the pain. Poisoning is the principal diagnosis, and chest pain is the secondary diagnosis. Provider documentation must be clear whether a diagnosis results from a toxic effect. For example, a patient is admitted with right hand cellulitis and documentation in the nurse’s notes reflects patient was bitten by a spider on the right hand the day before admission. Right-hand cellulitis due to spider bite provides clarity of the cause of the cellulitis. A toxic effect diagnosis would be the principal diagnosis and cellulitis would be a secondary diagnosis. Codes for underdosing should never be assigned as principal diagnosis or first listed codes. The exacerbation or relapse of a medical condition due to under dosing is the principal diagnosis. For example, seizure disorder will be principal when a patient is admitted after having a seizure and noted with subtherapeutic Dilantin levels. Additional Tips: Use as many codes as necessary to describe completely all manifestation of the adverse effect, poisoning, underdosing, or toxic effect. If two or more drugs, medicinal or biological substances are taken, code each individually The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined). If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Documentation of a change in the patient’s condition is not required in order to assign an underdosing code. Documentation that the patient is taking less of a medication than is prescribed or discontinued the prescribed medication is sufficient for code assignment. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded too. If marijuana is legalized for therapeutic/recreational use per state legislature (depending on the documentation in the chart), it is no longer considered an illicit drug. To capture an adverse reaction in this case, it would be coded as poisoning or adverse effect.