How do physical and occupational therapists calculate billable units in Texas?
Physical and occupational therapy billing in Texas depends on payer guidelines for timed codes (e.g. therapeutic exercise 97110, manual therapy 97140, neuromuscular re-education 97112). For Medicare Part B (Novitas Solutions Jurisdiction H) and commercial plans adopting federal guidelines, therapists must use the CMS 8-Minute Rule, where total timed minutes across all procedures are combined to determine the allowable units (8-22 mins = 1 unit; 23-37 mins = 2 units; 38-52 mins = 3 units; 53-67 mins = 4 units). Conversely, commercial plans following the Substantial Presentation Model (SPM / AMA rule) calculate units individually per procedural code based on an 8-minute midpoint threshold. When a patient exceeds annual Medicare therapy thresholds, modifier -KX must be appended to certify medical necessity.
1. Mastering the CMS 8-Minute Rule versus AMA Guidelines
Unit calculation discrepancies cause thousands of dollars in lost therapy revenue every month.
Therapists must know which rule applies: Novitas Medicare Part B and Texas Medicaid strictly enforce the cumulative CMS 8-minute rule, whereas some private commercial PPOs allow the AMA code-specific calculation method.
2. The Therapy Threshold and Modifier -KX Compliance
When patients require extended rehabilitation following major orthopedic surgeries, claims approaching the statutory Medicare threshold will be automatically rejected unless modifier -KX is present.
Appending modifier -KX attests that clinical documentation supports continued skilled therapy necessity as outlined in Novitas guidelines.