Don't wait for your MAC to alert you to an error -- be on the lookout for them. If you've been losing reimbursement to computer hiccups at your carrier, you're not alone. Earlier this year, thousands of Medicare recipients in one state were wrongly told their benefits were being cut by $300 -- but the state decided not to notify those affected with a letter. Instead, the state only told those who called in to complain that the notification of benefit cuts they received was the result of a computer glitch. Glitches can cause erroneous denials, unnecessary rejections, lost crossover claims, and frustrating delays. But if you don't notice the glitch, you can kiss your reimbursement goodbye. That's because the Medicare Administrative Contractor (MAC) won't always alert you to a mistake that its computers make. "If a computer glitch was due to a widespread problem, like there was no remittance generation for an entire day, there will usually be an announcement in the MAC's Web site," says Zia Clarkson, a coding, reimbursement, and practice management consultant in Long Island, N.Y., "They do not notify practices or providers individually." Although payers may perform notifications on large-scale errors, "accidental denial on an entire batch of claims for an area would probably be considered a small glitch and no announcement issued," Clarkson says. "Providers would find out by following claims, notice that those claims were never addressed and would inquire about them to find out that there had been a problem that was being corrected. Medicare will usually correct the claims in a sweep in cases like that." When you click the send button and the claim is off to the payer, you'd like to assume your payment is coming, but if you're not vigilant, your claims can disappear into your carrier's computers, never to be seen again. Therefore, you have to stay on top of your claims, advises Kathy Philp, CPC, director of billing with Praxis Health Group in Oklahoma City, Oklahoma.