And other changes to B12 testing under the new Medicare Benefits Schedule rules.
Homocysteine tests may be added to vitamin B12 tests reflexively on samples that come back inconclusive, as part of a suite of MBS item changes.
From 1 July, pathology labs can perform a total vitamin B12 or active vitamin B12 (holotranscobalamin) test as the first-line test when GPs request a vitamin B12 test.
The Medicare Item 66838 for these tests is now available once every 11 months instead of 12 months. And while active B12 is often more sensitive and better at earlier diagnosis, the MBS reimbursement has been dropped to align with the cheaper total B12 test – making an active B12 test more expensive out of pocket.
Instead of a total vitamin B12 test, pregnant patients and children will receive an active B12 test.
But if the results of either test come back inconclusive, the pathology lab can automatically analyse the sample for homocysteine or methylmalonic acid levels, using the MBS Item 66839. High levels of either of these metabolites support the diagnosis of B12 deficiency.
MBS Item 66839 can now only be ordered once every 11 months.
For total B12 tests, a borderline result is 180-350ng/L and for active B12 tests, a borderline result is 25-70pmol/L.
The MBS has also added the new 66842 item number for follow-up vitamin B12 assessment in patients whose B12 status was assessed in the past 11 months.
Prescribers will need to provide information that shows the test is eligible for the MBS rebate on the request form. Patients are eligible for a follow up test for total vitamin B12, active vitamin B12 and other vitamin B12 markers such as methylmalonic acid or homocysteine if they:
- Had inconclusive initial vitamin B12 test results
- Have risk factors for abnormal vitamin B12 levels, such as
- Low dietary intake
- Family history
- Previous abdominal or pelvic radiotherapy
- Previous gastrointestinal tract surgery
- Recreational nitrous oxide use, or
- Other clinical conditions with a risk of B12 deficiency
“There are no restrictions on the frequency or number of tests per year under item 66842, which allows the clinician to determine the appropriate testing frequency for the patient they are treating,” according to the MBS factsheet.
