What's considered a "current TB test result"?

I'm looking for jobs to apply for and see a lot of places asking for current TB test results. How long after getting the TB test done are the results valid for? Does it vary by state? By agency?
We have to have one yearly. When I switched jobs, my last PPD was accepted because it was still current..

So generally about a year? That sounds good to me. Thank you so much!

Some places like corrections or certain public health clinics might ask for 'within 6 months' because that's how often they test their employees.

Current test results are those within the previous 12 months. However, as amoLucia mentioned, some facilities may require more recent/frequent results.

Many places no longer do them annually for employees, but do a risk assessment. New hires usually do a two step upon hiring. I would guess a year?

Thank you all for answering my question, I really appreciate it. I was thinking somewhere between 6 months and a year would be considered valid, but I wasn't sure. Glad to know it's not typically required to be tested more often than that!