What is the advantage of 2-step indirect immunoassays over one-step methods?

In addition to its use in Down syndrome screening, inhibin A measurements have clinical applications in which of the following? 

Which hormone is necessary for normal GH secretion?

Which hormone is secreted in a diurnal rhythm, making saliva a useful medium for its measurement?

For quantitative determination of glucose in urine with the greatest accuracy and specificity, which methods are recommended? 

What role does ACTH play in aldosterone regulation?

Which drug is known to cause nephrogenic DI?

How is delta osmolality defined?

Why is uE3 considered the least stable of the screening analytes?

Why do immunoassays for progesterone have limited functional sensitivity?