Type of sample. Each type of planting needs a separate soil test. In general lime is used to raise pH, while sulfur is recommended to lower it. Apply lime and sulfur in summer when the soils are warm and microorganism activity is high. Though nitrogen is one of the key nutrients needed for plant growth, many labs won't test for it because of its high mobility.
Nitrogen leaches out of the soil easily, and levels can fluctuate through the growing season.
Since organic matter can hold and then slowly release nitrogen as it breaks down, some labs link the organic matter content to the nitrogen level in the soil. Alfalfa meal, cottonseed meal, urea, and fish meal are some fertilizer sources of nitrogen. Phosphorus levels are often reported as either available or reserve. Available phosphorus can be used now, while reserve is tied up due to pH or nutrient imbalance. Often, just raising or lowering the pH to the ideal 6.5 will free up phosphorus for plant use.