There are two types of tests to answer this question, soil tests and tissue tests.
Soil tests reveal the nutrient levels are in the soil.
Tissue tests give an accurate picture of the nutritional status of the plants. Because perennial fruit crops have large root systems and recycle nutrients from year to year, tissue testing is a better way to determine plant nutrient needs. The extra information in a tissue test is well worth the cost. Too much nitrogen fertilizer results in excess vegetative growth and reduces the reproductive growth that we need to maintain large yields of fruit. In apples, excess nitrogen can result in soft fruit with poor color.