Common Mistakes Library
Learn from real-world coding errors with before/after examples and prevention strategies
Showing 12 mistakes
❌ Incorrect
ICD-10: E11.9 (Type 2 diabetes without complications) - Tier 3
✅ Correct
ICD-10: E11.65 (Type 2 diabetes with hyperglycemia) - Tier 1 ✓
Financial & Compliance Impact:
Lost Tier 1 capture = $1,500-$3,000 per patient in reduced reimbursement
Real-World Example:
Patient admitted with stroke. Chart shows 'diabetes' in history. Coordinator codes E11.9. However, admission glucose was 340 mg/dL and patient on insulin. Should have queried physician for E11.65 (hyperglycemia) to capture Tier 1.
How to Prevent This Mistake:
Always review lab values, medication list, and physician notes for evidence of complications (neuropathy, retinopathy, nephropathy, hyperglycemia, hypoglycemia)
❌ Incorrect
ICD-10: J44.9 (COPD, unspecified) - Tier 3
✅ Correct
ICD-10: J44.1 (COPD with acute exacerbation) - Tier 1 ✓
Financial & Compliance Impact:
Missed Tier 1 opportunity, underpayment of $2,000-$4,000
Real-World Example:
Patient with hip fracture has COPD history. Coordinator codes J44.9. Chart review shows patient required increased albuterol treatments during acute stay and was on 2L O2. Should have queried for J44.1 or J96.11 (chronic respiratory failure with hypoxia) for Tier 1.
How to Prevent This Mistake:
Review respiratory section of H&P, check for recent hospitalization, oxygen requirements, nebulizer treatments, or increased dyspnea
❌ Incorrect
No malnutrition code documented despite low albumin and weight loss
✅ Correct
ICD-10: E43 (Severe protein-calorie malnutrition) - Tier 1 ✓
Financial & Compliance Impact:
Lost Tier 1, potential MAC audit flag for missing obvious comorbidity
Real-World Example:
Stroke patient, albumin 2.4 g/dL, lost 15 lbs in hospital. Coordinator didn't code malnutrition. Dietitian note stated 'severe malnutrition.' Should have coded E43 for Tier 1 capture.
How to Prevent This Mistake:
Check albumin, prealbumin, BMI, recent weight loss, dietitian notes. Query if albumin <3.0 or unintentional weight loss >10% in 6 months
❌ Incorrect
Bladder Management: 7 (Complete Independence) - Patient has scheduled q2h toileting
✅ Correct
Bladder Management: 5 (Supervision/Setup) - Requires scheduled reminders ✓
Financial & Compliance Impact:
Inflated FIM scores trigger MAC audit, potential overpayment recoupment
Real-World Example:
Brain injury patient. Coordinator scored bladder as 7 based on 'no accidents.' Nursing notes showed q2h scheduled toileting. MAC audit caught this, facility had to return $8,500 in overpayment plus interest.
How to Prevent This Mistake:
Review nursing flow sheets for actual continence status. If patient needs reminders, prompts, or scheduled toileting, cannot score 6-7
❌ Incorrect
Transfer Bed/Chair: 4 (Minimal Assist) - PT supervises for safety, patient performs independently
✅ Correct
Transfer Bed/Chair: 6 (Modified Independence) - Patient independent with device, supervision for safety ✓
Financial & Compliance Impact:
Artificially low admission FIM reduces CMG payment and limits potential for functional gain documentation
Real-World Example:
Hip fracture patient transfers independently with walker but PT supervises. Coordinator scored 4. Should be 6. This cost facility $1,200 in lower CMG assignment.
How to Prevent This Mistake:
Distinguish between physical assistance and supervision for safety. If patient performs task independently but therapist watches, score 6 (Modified Independence), not 4-5
❌ Incorrect
Query: 'Does patient have any complications from diabetes?' - No response from physician
✅ Correct
Query: 'Patient's admission glucose 340 mg/dL, on insulin. Does this represent Type 2 diabetes with hyperglycemia (E11.65)?' - Physician responds 'Yes' ✓
Financial & Compliance Impact:
Missed tier capture opportunity, delayed assessment completion
Real-World Example:
Coordinator sent vague query about CHF. No response after 5 days. Revised query with specific ejection fraction, diuretic dose, and suggested code. Physician responded same day.
How to Prevent This Mistake:
Always include specific clinical indicators (lab values, symptoms, treatments) and suggest specific ICD-10 code for physician to confirm or clarify
❌ Incorrect
Preadmission living setting: Unknown - Assessment submitted incomplete
✅ Correct
Coordinator contacts family, reviews acute hospital social work notes, obtains preadmission living setting ✓
Financial & Compliance Impact:
MAC audit flag, potential denial of payment for incomplete assessment
Real-World Example:
Coordinator couldn't find preadmission living info, submitted 'unknown.' MAC audit denied payment. Had to retrospectively obtain info and resubmit, delaying payment 45 days.
How to Prevent This Mistake:
Never submit assessment with critical fields blank. Contact family, review acute records, or query physician/social worker
❌ Incorrect
Patient admitted Monday, assessment completed Friday (day 5) - Compliance violation
✅ Correct
Patient admitted Monday, assessment completed Wednesday (day 3) ✓
Financial & Compliance Impact:
Compliance violation, MAC audit trigger, potential payment denial
Real-World Example:
Facility had 15% late assessments. MAC audit resulted in $75,000 payment recoupment. Implemented daily tracking system, late assessments dropped to <2%.
How to Prevent This Mistake:
Prioritize new admissions, complete within 24-48 hours. Use daily workflow checklist to track deadlines
❌ Incorrect
Coding 'History of MI 10 years ago' as active cardiac comorbidity - Tier inflation
✅ Correct
Only code comorbidities that are currently being treated or affecting rehabilitation ✓
Financial & Compliance Impact:
Tier inflation, MAC audit flag for overcoding, potential fraud investigation
Real-World Example:
Coordinator coded old MI from 15 years ago. Patient not on cardiac meds, no current cardiac issues. MAC audit flagged as inappropriate tier inflation. Had to defend coding decision.
How to Prevent This Mistake:
Verify comorbidity is ACTIVE: currently on medication, requiring monitoring, or impacting rehabilitation plan
❌ Incorrect
I63.9 (Cerebral infarction, unspecified) when chart specifies left MCA stroke
✅ Correct
I63.512 (Cerebral infarction due to unspecified occlusion of left middle cerebral artery) ✓
Financial & Compliance Impact:
Less accurate data reporting, potential audit flag for lazy coding practices
Real-World Example:
Facility consistently used I63.9 for all strokes. MAC audit noted lack of specificity. Required retraining and retrospective chart review to improve coding accuracy.
How to Prevent This Mistake:
Always review radiology reports, physician notes for anatomical specificity. Use most specific code available
❌ Incorrect
ICD-10: D64.9 (Anemia, unspecified) - Tier 3
✅ Correct
ICD-10: D62 (Acute posthemorrhagic anemia) - Tier 1 if transfusion given ✓
Financial & Compliance Impact:
Lost Tier 1 capture worth $1,500-$2,500
Real-World Example:
Hip fracture patient received 2 units PRBCs in acute hospital. Coordinator coded D64.9. Should have queried for D62 (acute posthemorrhagic anemia) to capture Tier 1.
How to Prevent This Mistake:
Review acute hospital records for transfusions. If patient received blood products, query for acute anemia diagnosis
❌ Incorrect
Admission Eating: 5, Discharge Eating: 4 - Patient regressed? Likely scoring error
✅ Correct
Consistent scoring methodology, functional improvement documented ✓
Financial & Compliance Impact:
MAC audit flag, questions about quality of care or data integrity
Real-World Example:
Coordinator rushed discharge assessment, scored eating lower than admission. MAC audit questioned regression. Had to provide detailed explanation and corrected documentation.
How to Prevent This Mistake:
Review FIM scores for logical progression. If discharge lower than admission, verify accuracy and document medical reason