The Form 26AS contains details of tax deducted on behalf of the taxpayer (you) by deductors(employer, bank etc.). So, TDS deductions that are given in Form 16 / Form 16 A can be cross checked using Form 26AS. The TDS amounts reflected in Form 26AS and Form 16/16A should always be the same.
(If there are discrepancies, the IT dept will consider the TDS figures as per Form 26AS only. You need to contact the TDS deductor to rectify any errors. For example– If your employer has updated your PAN wrongly, TDS deduction will not get reflected in your From 26AS. In this case, you need to get this error rectified by your employer.)