As with case law, statutes are constantly evolving. Before relying on a statute as authority, you must verify that it has not been amended or repealed.
Start by checking the annual pocket parts and updated supplements. The unoffical versions of the Code (U.S.C.A. and U.S.C.S.) are generally updated monthly. However, the print version supplements are often issued too slowly to provide thorough updating, so it may be best in this case to use online sources.
All online versions of the U.S. Code are regularly updated to include recent session laws too new to be incorporated in print version updates. This information generally accompanies each section of the Code. Check the currency information at the beginning of the code or code section.
On Westlaw, use KeyCite to identify pending legislation that may affect the statute.
On Lexis, use Shepards to identify pending legislation that may affect the statute.
Proposed legislation - For the current Congress, separate bill summary & status and bill text databases on Thomas can be keyword (or index) searched by date for proposed additions or amendments to the U.S. Code. Congressional bills are also keyword searchable on GPOAccess. The U.S. Code Classification tables also show recent additions and amendments to the U.S. Code.
Judicial history: To establish the current validity of an existing statute the caselaw of the courts of the jurisdiction in which it governs should also be searched for supreme court constitutionality rulings and other holdings affecting its "good law" status. Lexis Shepard's and KeyCite on Westlaw, in addition to tracing legislative changes, also assist in determining the judicial history of statutory provisions.
Below are links to assist in verifying the current status of a statute.