Diagnosis of rickets does not represent complexity today. The disease has to be detected by the pediatrician during clinical examination on the basis of well-known symptoms and laboratory diagnostic methods of this disease. And, nevertheless, in more than 50% of cases the diagnosis rickets in time is not made.

Let's dwell upon laboratory diagnostics. The earliest and sensitive indicator of presence of rickets is increase in level of alkaline phosphatase in blood serum, at the same time this marker often advances the above clinical symptoms and biochemical changes.

Changes of level of calcium and phosphorus in blood serum in rickets usually have phasic character.

In the first stage of hypovitaminosis of D the absorption of calcium in intestines decreases that leads to decrease in its quantity in blood (hypocalcemia). In this stage the content of phosphorus remains normal.

The lack of calcium stimulates production of parathormone which leads to increase in level of calcium in blood in the second stage , but at the same time absorption of phosphorus and amino acids in kidneys oppresses that leads to decrease in Phosphorus in blood (hypophosphatemia).

The third stage – at further deficiency of vitamin D changes sensitivity of bones to excess of parathormone that leads to reduction of extraction of calcium from bones and to emergence of a hypocalcemia in blood against the background of a fosfaturiya (the raised discharge of phosphates with urine) and hypophosphatemia (the lowered content of phosphates in blood).
Also for detection of rickets the test of urine is widespread on Sulkovich. This analysis defines concentration of calcium, and subsequently it helps to trace treatment outcome though not always is reliable.
Besides, in hard cases do the roentgenogram on which it is possible to see extent of disturbance of a mineralization of bones. However such method is not suitable for early diagnosis of rickets.