Each 20 mg dose of fosfomycin disodium given by injection

This code represents the intravenous formulation of fosfomycin disodium, a broad-spectrum phosphonic acid antibiotic, billed per 20 mg. The IV formulation (distinct from the oral fosfomycin tromethamine used for uncomplicated UTIs) is used to treat serious systemic infections, particularly those caused by multidrug-resistant (MDR) organisms. It is typically administered in combination with other antibiotics to reduce resistance emergence.

This code applies when fosfomycin disodium is administered intravenously in inpatient or outpatient infusion settings for serious infections such as complicated UTIs, hospital-acquired pneumonia, bacteremia, or osteomyelitis caused by MDR pathogens including MRSA, carbapenem-resistant Enterobacterales (CRE), or Pseudomonas aeruginosa. Documentation should include the administered dose in milligrams, route of administration, and the treating diagnosis to support medical necessity. Units billed must reflect the total dose administered divided by 20 mg per unit.

• Unit calculation is critical: Doses are commonly 12–24 g/day; a 4 g dose = 200 units. Underbilling due to miscalculation of units is a frequent error.
• Do not confuse with oral fosfomycin: Fosfomycin tromethamine (oral granules for UTI) is reported under a different code; this code is specific to the IV disodium salt formulation only.
• Payer coverage varies significantly: IV fosfomycin may require prior authorization and documentation of MDR organism susceptibility testing or failure of first-line agents; some payers classify it as non-covered or investigational without supporting clinical evidence in the record.