Interesting. US middle class parameters are so wide that they're all but meaningless. The general definition is a 3 person household with an annual income between 67% and 200% of the national median income, so anywhere between $56K and $170K. A huge range. In most of the country, 3 people would be hard put to survive on $56K per annum.
In California, most if not all the couples I know in their 30s-40s have combined incomes over $170K, but would not consider themselves in the upper range of middle class, never mind upper class.
Blue or white collar jobs in the US are defined by job type rather than salaries. Blue collar work usually involves manual labor of some kind, though many require special skills (like welders, or electricians). White collar jobs tend to be clerical, office or managerial work. The "white collar" designation goes back 100 years ago when men wore (white) shirts and ties to office jobs.
In the US, "working class" is a rarely used descriptor.