Final answer:
The medical biller should review and correct any errors on the rejected claims before quickly resubmitting them to the clearinghouse for processing.
Step-by-step explanation:
The next step the medical biller should take after receiving notice that 20 claims were acknowledged and 10 claims were rejected is to resubmit the rejected claims. Before resubmission, it is crucial to review the reasons for rejection to correct any issues, such as coding errors, missing information, or non-compliance with payer policies. Additionally, it is important to act quickly as there may be a deadline for resubmission to ensure that the healthcare provider receives reimbursement in a timely manner.