What is the lowest score on Middle School Content Knowledge Praxis?

There isn't a published "lowest score" for the Praxis Middle School Content Knowledge tests (because there are multiple tests depending on the specific content area). Praxis scores are reported as scaled scores, not raw scores. The range of scaled scores varies by test form. A failing score is generally below a certain threshold, but this threshold isn't a fixed number publicly released by ETS (the company that administers the Praxis exams). You'll need to consult the specific passing score information for the *exact* Praxis Middle School Content Knowledge test you're referring to on the ETS website.