CMS Pub. 100-04, ch. 20, § 100.2.3.1

Necessity for Oxygen

(Rev. 1, 10-01-03)

Recertification scheduling and documentation requirements depend on the date when

home oxygen therapy began. DME MACs request the following information on all

recertifications:

• Date and results of the most recent arterial blood gas or oximetry tests prior to the

recertification date;

• Name of the provider conducting the most recent arterial blood gas or oximetry

tests performed prior to the recertification date and the conditions under which

this test were conducted; and

• Estimated length of need for oxygen (Section B on the Form CMS-484).

DME MAC establish the schedule for recertifying the need for oxygen for patients

beginning home oxygen therapy in accordance with the requirements below:

1. Recertifications

Group I: Recertification requirements are to be determined by the DME MAC.

Group II: If oxygen test results on the initial certification were in Group II, according to

§1834(a)(5) of the Act, recertification of all oxygen patients must be performed within 90

days after initial certification for all patients who begin coverage after January 1, 1991,

with an arterial blood gas result at or above a partial pressure of 55 mm Hg or an arterial

oxygen saturation percentage at or above 89. Repeat blood gas study must be performed

between the 61st - 90th day of home oxygen therapy. Retesting is required only if a claim

for oxygen therapy will be filed for the fourth or later months.

If recertification is due, DME MACs do not pay the next month's claim if the test was not

performed during the required time frame. If a qualifying test is not obtained between the

61st and 90th day of home oxygen therapy, but the patient continues to use oxygen and a

test is obtained at a later date, DME MAC instruct suppliers to use the date of the repeat

test as the date of service on a subsequent claim, and if that test meets Group II criteria,

they resume payments from that point of time.

2. New Orders - In the following situations, a new order must be obtained and kept

on file by the supplier, but neither a new CMN nor a repeat blood gas study are

required:

• If the prescribed maximum flow rate changes but remains within one of the

following categories: (a) less than 1 LPM, (b) 1-4 LPM, (c) greater than 4 LPM

• If the physician has initially specified a delivery system, and a change is made

from one type of stationary system to another (i.e., concentrator, liquid,

gaseous).