TT #289 · Parshas Tazria · Aliyah 7 · Passuk 55
English: The priest shall examine the lesion after it has been washed; if the lesion has not changed in appearance and has not spread, it is impure; you shall burn it in fire. It is a penetrating decay, whether the worn or unworn side is affected.
Torah Temimah cites Sifra (Toras Kohanim) for applying the post-washing examination to every material category subject to the law.
Sifra — Vayikra 13, Midrash Sefer
English: The phrase “its appearance” applies to every material that can become impure through this garment-affliction.
Textual derivation
The post-washing examination applies across each material category that can be rendered impure by garment tzaraas.