1. Skip to Menu
  2. Skip to Content
  3. Skip to Footer

Alkaline Phosphatase (ALP)

Alkaline phosphatase refers to a family of enzymes that catalyze hydrolysis of phosphate esters at an alkaline pH.ALP is present (in decreasing order of abundance) in placenta, intestine, kidney, bone and purchasing cialis with next d ay delivery liver. In adults, more than 80% of serum ALP activity derives from liver and bone. In late pregnancy, placental ALP is increased. In children and adolescents most serum ALP activity originates in osteoblasts and correlates with the rate of canadian healthcare cialis bone growth. The serum half‑life is seven days.

Several caveats must be remembered in interpreting ALP results:

  • ALP levels should always be measured after fasting because enzyme levels increase as much as 30 U/L after food ingestion. Patients with blood group O and B who are secretors can have increased ALP levels after eating a fatty meal because of the release of intestinal enzyme.
  • African Americans have 10 to 15% higher ALP serum levels than Caucasians.
  • In children, ALP is increased up to 3 times the upper limit of normal and in pregnant patients it can be increased up to 2 times normal.
  • ALP levels may double following bone fracture.
  • Smokers have 10% higher ALP levels than nonsmokers do.
  • ALP levels fluctuate approximately 6% from week to week in a healthy individual.

ALP is most useful in diagnosing cholestatic liver diseases.Bile duct obstruction results in increased synthesis of ALP by bile duct epithelial cells and release of ALP into the good choice serum. Alkaline phosphatase may be increased even if only a few small bile ducts are obstructed and serum bilirubin is normal. Serum ALP often exceeds four times the upper limit of normal in extrahepatic and how to get cialis in canada intrahepatic cholestasis. The most common causes of extrahepatic cholestasis are pancreatic cancer, common duct stones and strictures, and primary sclerosing cholangitis. Intrahepatic cholestasis is www.asian-oasis.com usually due to primary biliary cirrhosis or drug reactions (erythromycin, chlorpromazine, estrogens, and methyltestosterone). Patients with primary sclerosing cholangitis and primary biliary cirrhosis initially have elevated ALP and normal bilirubin levels.

When the ALP level is increased disproportionately to the bilirubin level (e.g. a bilirubin <1.0 mg/dL and ALP >1000 U/L), granulomatous or infiltrative diseases of the liver are likely. Possible diagnoses include sarcoidosis, fungal infections, tuberculosis, and lymphoma. ALP levels are also increased in hyperthyroidism, cardiac failure, lymphoma, and hypernephroma.

Lower ALP levels (<3 times the upper limit of normal) are less specific for cholestatic liver disease and may be seen with hepatocellular diseases such as acute viral hepatitis, chronic hepatitis, and cirrhosis. However, it is important to viagra online buy remember that incomplete obstruction by gallstones may produce mildly elevated ALP levels. Intrahepatic cholestasis secondary to anabolic steroids or birth control pills may cause mild increases in ALP. Gamma glutamyltransferase (GGT) can be measured to determine if elevated ALP levels are of cialis 20 mg tablet liver origin; increased GGT indicates that ALP is most likely from the liver.

Medications that have been reported to increase ALP include; allopurinol, anabolic steroids, captopril, carbamazepine, chlorpromazine, chlorpropamide, diltiazem, erythromycin, estrogens, flutamide, gold salts, methimazole, methyltestosterone, phenothiazines, phenylbutazone, phenytoin, quinidine, sulfonamides, tolazamide, tolbutamide, trimethoprim-sulfamethoxazole, valproic acid, and verapamil.

Sometimes it is useful to look at the relationship of ALP to bilirubin and lactate dehydrogenase (LD) levels.

Pathology

ALP

Bilirubin

LD

Intra or extrahepatic cholestasis

Increased

Increased

Normal

Focal benign cholestasis

Increased

Normal

Normal

Focal malignant cholestasis

Increased

Normal

Increased

 

Osteoblastic bone disease can also increase serum ALP. The most common bone disorders associated with elevated ALP are; Paget’s disease, osteomalacia, hyperparathyroidism, osteogenic sarcoma, and bone metastases.

Low alkaline phosphatase levels have been reported in patients with magnesium deficiency, hypothyroidism, malnutrition, hemolytic anemia, Wilson’s Disease, post coronary bypass surgery, estrogen replacement therapy, and congenital hypophosphatasia. Blood transfusion causes transient decreases in ALP, due to chelation of cations by citrate.

Reference range in adults is 40 - 125 IU/L (Vitros Analyzer).

Specimen requirement is one SST tube of blood. If blood is collected in a citrate or EDTA tube, ALP activity will be almost totally inhibited due to the chelation of zinc and magnesium, which are necessary enzyme cofactors.

Other Articles of Interest
  • Acanthamoeba Keratitis...
    Clinicians evaluating contact lens users with symptoms of eye pain or redness, tearing, decreased vi...
  • Acid Phosphatase...
    The introduction of an immunoassay for prostatic acid phosphatase (PAP) in 1977 was hailed as a brea...
AddThis Social Bookmark Button

Stay Informed

Amazon Book

Our Sponsors

Login Form

Mobile Applications

iPad iPod Promo-2012

Get it for: iPhoneiPad

ClinLab Navigator Information

McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
© 2012 ClinLab Navigator, LLC.