Answers:
I don't know something like the "broad rule" to see a doc. for WBC > 30 ...
Normal compass is ~4 - 11 ... you've apparently already see a doc. What's his warmth? Children's Motrin fluid works okay for the frenzy (and taste approaching grape). It also help near the cramp, making it easier for you to offer him his antibiotics.
Make sure to follow the Dr's direction in relation to the antibiotics -- your son wants to finish adjectives of them (to prevent the complication of a drug-resistant streptococcal infection).
His white count is slightly large, which is consistent near his infection (but at hand are different types of white blood cell, the differential (e.g. lymphocytes, eosinophils, basophils, band, etc.) will put the WBC effectiveness into proper context and treatment (and any further investigation) would be base on that.
Hope he get better soon!
General rule... over 30, dance to the Doc.
30.5 is reasonably giant a white count; most reference ranges for typical is between 4-11. might be a lab error; the prominent article is to see if this white count reduce while your son is on antibiotics; this is how they determine that the infection is on the road to recovery