Alkaline Phosphatase (ALP) are a group of enzymes present in our body. It is a hydrolase enzyme, primarily found in the liver as isoenzyme ALP-1 and in the bones as isoenzyme ALP-2. It is also produced by placenta and proximal convoluted tubules of the kidney. Isoenzyme ALP-3 is secreted in small quantities by cells lining the intestines. These tissues release alkaline phosphatase into the blood. The enzyme requires an alkaline pH (~10) for its activity. It cleaves the phosphorous group from molecules like proteins, nucleotides, and alkaloids by a process known as dephosphorylation. High alkaline phosphatase levels in the blood is detected by clinical diagnostic tests and may signify some bone, liver, intestinal, or placental disorder.
Osteoblastic or bone conditions like bone diseases and bone cancers lead to high levels of alkaline phosphatase. During bone growth, the activity of osteoclasts are increased, which elevates the ALP levels. When the activity of osteoclasts are increased, the rate of bone breakdown also increases. Sometimes, there is an abnormal bone breakdown accompanied by pain, skeletal deformities, and elevated ALP levels. This disease is known as Paget's disease. Other symptoms are osteomalacia, rickets, bone sarcomas, and bone metastasis.
Liver congestion or cholestasis raises the level of alkaline phosphatase in the blood. Obstruction of the biliary tracts due to gallstone or tumor, liver cancer, hepatitis, and liver damage due to toxins increases the ALP level.
During delayed pregnancy the placenta produces alkaline phosphatase which is above the normal level. This is also one of the reasons behind elevated ALP levels in blood.
Apart from bone and liver diseases, there are a few other symptoms. They are listed as follows:
- Increased intake of oral contraceptives
- Congestive heart failure
- Obstructive pancreatitis
- Herpes Zoster infection (Shingles)
- Parathyroid glands overactivity
- Adrenal cortical hyperfunction
- Gastrointestinal inflammation
- Systemic infections
- Rheumatoid arthritis
- Hodgkin's Lymphoma
- Gynecologic malignancies
- Myocardial or pulmonary infarctions
Alkaline Phosphatase (ALP) Test
The optimal level of ALP depends on your age, stage of growth, and activity of osteoblasts and osteoclasts. During adolescence, you will have slightly higher levels while for an adult, 50-75 mg/dl is considered a reasonable range.
A test for alkaline phosphatase (ALP) is done to check for liver and bone disorders. It is a test to measure the total amount of ALP enzyme present in the blood. ALP test is done if you have symptoms of jaundice, stomach pain, vomiting, and nausea. It is also done to check if any medication is harmful for the liver. ALP test also detects the level of parathyroid hormone that controls the growth of bones. The test also indicates if the treatment of any particular disease (e.g. Paget's disease) is working or not. The test is also performed sometimes to detect alcoholism, renal cell carcinoma, liver cirrhosis, gallstones, endocrine neoplasia, malnutrition, protein deficiency, etc.
In case you observed any of the aforementioned symptoms, do not hesitate for a medical check up. ALP test is simple and is done in almost every good clinic. Get the right treatment done from a doctor for speedy recovery.
Disclaimer: This HealthHearty article is for informative purposes only, and should not be used as a replacement for expert medical advice.