Question
My child was just born, and the test showed that the phenylalanine level is high, possibly indicating congenital phenylketonuria. What is the standard concentration of phenylalanine in the blood for phenylketonuria?
Answer
Phenylketonuria is a common amino acid metabolism disorder, typically diagnosed by measuring the level of phenylalanine in the blood. Normally, the concentration of phenylalanine should be between 0.06 and 0.18 mmol/L. When the concentration of phenylalanine exceeds 120 mmol/L, it may indicate a positive result, and further confirmation is needed. Additionally, measuring the level of tyrosine in the blood may provide better diagnostic results, as it allows for comparison of the ratio between phenylalanine and tyrosine. If the test results are affected by blood contamination, it may lead to inaccurate results. It is recommended to consider all relevant indicators for diagnosis.