Serum phenylalanine

The conversion of phenylalanine to tyrosine in the body must involve phenylalanine hydroxylase. If the body lacks phenylalanine hydroxylase, phenylpropionic acid metabolism disorder will occur, so that phenylalanine can not be converted into tyrosine, and it is converted into phenylpyruvate and discharged from urine, which is called phenylketonuria. At this time, the patient's plasma phenylalanine increased and tyrosine decreased.

Basic Information

Specialist classification: Digestive examination classification: biochemical examination

Applicable gender: whether men and women apply fasting: fasting

Tips: Do not eat too greasy, high-protein foods the day before the blood draw, avoid heavy drinking. After 8 pm on the day before the medical examination, you should start fasting for 12 hours, and take the blood on an empty stomach the next morning to avoid affecting the test results. Normal value

1, fluorescent color method:

Newborn: 73 ~ 206μmol / L.

Adult: 46 ~ 109μmol / L.

2. Ion exchange chromatography:

Newborn: 42 ~ 110μmol / L.

Adult: 37 ~ 88μmol / L.

Clinical significance

1. Hyperphenylalaninemia is a group of metabolic disorders caused by defects in congenital phenylalanine hydroxylase. According to the defects of enzymes, it is divided into 1 typical phenylalanineuria, which is styrene-acrylic. The enzyme protein of the hydroxylase is completely deficient; 2 the enzyme protein of the benign type is phenylalanine hydroxylase is not completely lacking; 3 the temporary hyperphenylalaninemia is delayed by the maturation of the enzyme protein. All three types are autosomal recessive.

2. Albinism is caused by a decrease in melanin production due to defects in tyrosine oxidase or due to melanosome metastasis.

3, Parkinson's syndrome is a senile disease, it is due to decolorization and melanocyte loss in the substantia nigra of the patient, the area of ​​dopamine, norepinephrine and serotonin decreased, with dopamine reduction Most obvious, especially at the caudate nucleus and the nucleus. Since dopamine and ortho-renin are tyrosine derivatives and serotonin is derived from tryptophan, Parkinson's syndrome is considered to be a non-hereditary amino acid metabolic disease.

High results may be diseases: phenylketonuria precautions

First, the precautions before blood draw

1, do not eat too greasy, high-protein food the day before the blood, to avoid heavy drinking. The alcohol content in the blood directly affects the test results.

2. After 8 pm on the day before the medical examination, you should start fasting for 12 hours, and take the blood on an empty stomach the next morning to avoid affecting the test results.

3, should relax when taking blood, to avoid the contraction of blood vessels caused by fear, increase the difficulty of blood collection.

Second, should pay attention after blood draw

1. After blood is drawn, local compression is required at the pinhole for 3-5 minutes to stop bleeding. Note: Do not rub, so as not to cause subcutaneous hematoma.

2, the pressing time should be sufficient. There is a difference in clotting time for each person, and some people need a little longer to clotting. Therefore, when the surface of the skin appears to be bleeding, the compression is stopped immediately, and the blood may be infiltrated into the skin due to incomplete hemostasis. Therefore, the compression time is longer to completely stop bleeding. If there is a tendency to bleed, the compression time should be extended.

3, after the blood draw symptoms of fainting such as: dizziness, vertigo, fatigue, etc. should immediately lie down, drink a small amount of syrup, and then undergo a physical examination after the symptoms are relieved.

4. If there is localized congestion, use a warm towel after 24 hours to promote absorption.

Third, avoid specimen hemolysis, otherwise it will lead to a false increase in results.

4. Please inform the doctor about the recent medication and special physiological changes before the test.

5. Once the baby is diagnosed with PKU after birth, a low phenylalanine diet should be given immediately.

Inspection process

Take 2 ml of empty blood, not anticoagulation, and immediately send the test. The detection method is the same as the fluorescent color method.

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Adverse reactions and risks