TENS Unit

Can anyone help me with billing for TENS unit?
Thanks!

Tens

What site of service?
Payment of 10 percent of the purchase price, i.e., 10 percent of the purchase fee schedule amount for the item less coinsurance and any applicable deductible is allowed for the first 2 months of usage for a 2 month trial period prior to purchase. This permits an attending physician time to determine whether the purchase of a TENS is medically appropriate. If so, the full purchase price is paid without an adjustment for the two monthly rental payments. Bill your DMERC for TENS for the 2 month rental period and for the actual purchase. The HCPCS codes for TENS are E0720 (two lead) and E0730 (four or more leads, multiple stimulation). The HCPCS codes for TENS supplies are A4557 (Carrier Discretion), A4595 (Special Coverage Instructions), and E0731 (Special Coverage Instructions).
IOM: 100-03,2, 160.2; 100-03,4, 280.1 (Medicare manual).
A TENS unit may be used with either 2 leads or 4 leads, depending on the characteristics of the patient's pain. If it is ordered for use with 4 leads, the medical record must document why 2 leads are insufficient to meet the patient’s needs.
Separate allowance will be made for replacement supplies when they are medically necessary and are used with a TENS unit that has been purchased and/or approved by Medicare. If 2 TENS leads are medically necessary, then a maximum of one unit of Code A4595 would be allowed per month; if 4 TENS leads are necessary, a maximum of two units per month would be allowed. If the use of the TENS unit is less than daily, the frequency of billing for the TENS supply code should be reduced proportionally.
Replacement of lead wires (A4557) more often than every 12 months would rarely be medically necessary.