Medicare is an accident waiting to happen. According to current projections, its trust fund runs dry in about 10 years.

You -- the 28.4 million elderly and disabled beneficiaries of Medicare -- will have to pay more of your medical bills next year, in order to save the government some money. About $426 million in real program cuts were included in the 1982 budget.

But Medicare officials say that's only a drop in the bucket compared with the money that is really needed to put the program back on a sound financial basis.

Dream-world politicians want to borrow money from Medicare's limited trust fund in order to bolster the struggling Social Security retirement fund. Doing this, they say, will make it unnecessary to raise the retirement age or make other money-saving changes in Social Security benefits.

That kind of thinking is not only delusionary, it is downright dangerous. It will only defer the inevitable decision on retirement benefits, while causing the Medicare trust fund to go broke sooner.

The current round of cost increases for Medicare beneficiaries starts this Jan. 1. The highlights:

Hospital insurance. You are now paying the first $206 of each hospital bill, before Medicare kicks in. Next year you will pay $256 (up from the $248 expected under the old law). By 1984 -- less than three years away -- you will be paying an estimated $328 of each hospital bill out of your own pocket.

Doctor bills. You now pay the first $60 of each bill. Next year, you'll pay the first $75.

Other technical adjustments in the program will further increase your personal share of medical costs.

An important change has also been made in the enrollment period for Part B of Medicare, which covers doctor bills.

Last year, you could enroll at any time and be covered immediately. But starting Jan. 1, 1982, Medicare will revert to an older, and more restrictive, rule.

If you do not apply for the doctor bills portion of Medicare within three months of the month you turn 65, you will not be eligible again until the next general enrollment period, which is Jan. 1 through March 31 of each year. Coverage then begins the following July 1.

Any doctor bills you incur before coverage begins are not insured, so you could lose a lot of money by failing to sign up on time.

Medicare Part B now costs $11 a month, up from $9.60 last year. Your premium rises by 10 percent for each 12-month period when you could have been enrolled but weren't. (Part B is 30 percent funded by these insurance premiums and 70 percent by general tax revenues. Only Medicare hospitalization, Part A, is funded by the Social Security tax.)

You can apply for Medicare hospitalization at any time after age 65 and be covered immediately. If you don't apply at 65 and later fall ill, Medicare covers your hospital bills retroactively, but for no longer than six months back. (Doctor bills are not covered retroactively.)

If you are 65 or over and receiving Social Security benefits, you will generally be enrolled automatically in both Medicare plans. Monthly payments for Part B are deducted from your Social Security check.

But if you're still working at 65 you have to apply. As a general rule, private health insurance after 65 only fills the gaps in Medicare, so for complete coverage it is essential to be on the government's health insurance rolls.

Medicaid, for the poor and near-poor, is also being cut back. The 1982 budget reduces the amount of money that the federal government will pay toward state Medicaid plans (which cover 21.6 million people, 10.5 million of them children). It is up to the states to decide which Medicaid clients, if any, to cut off.

The second round of 1982 budget cuts proposes further reductions in health insurance. And there's yet another cost of cutting Medicare:

When the government covers less, your private, old-age health insurance has to cover more, which means that your private health-insurance premiums will be going up.