phos test, blood
Alkaline phosphatase, serum:
This is a serum enzyme produced by the bones (and reflective of
bone-growth activity), the liver, and the placenta. In growing
persons, elevation often reflects normal bone growth; and we used
to "heat fractionate" the patient serum into the "heat
stable" and "heat labile" (bone) components. If
an elevated AP became normal after the serum was heated at 56 degrees
C., the elevation was presumed to be due to a bone source.
Now, if AP is elevated and GGT/GGTP is
not elevated, the AP elevation is presumed due to a bone source.
- within normal range: (pending)
- normal people
- certain cases of metastatic neoplasia into liver and/or
- liver disease (liver fraction of AP...heat stable):
- obstructive jaundice (even pericholangitis as in abdominal
- hepatocellular jaundice
- hepatic venous outflow obstruction with biliary changes
can give AP >10004
- space occupying liver lesions, diffuse or segmental
- bone disease (bone fraction...heat labile):
- increased bone turnover (hyperparathyroidism; rickets;
Paget's disease; healing fractures)
- placental disease (syncytial trophoblastic fraction...PLAP):
- pregnancy (especially 3rd trimester).
- ovarian, testicular, and germ tumors.
- intestinal epithelial damage (strangulation/obstruction).
- kidney/renal tubule damage/tumors...RCC.
- congestive heart failure.
- 1-3 weeks after pulmonary infarct.
- CMV & EBV mononucleosis.
- dozens of medications3
- pernicious anemia/low serum B12 (osteoblasts need T4 & B12)
- milk alkali syndrome
- hypophosphatasia of any cause
- celiac disease
- Whipple disease
- folic acid deficiency
- zinc deficiency of any etiology (dialysis or TPN, etc.)
Test synonyms: AP; alk phos.
- 1. Interpretative Pathology...the Lufkin Difference, R. L.
Reece, M. D. 1977
- Becker's Endocrinology (p1509) (Military Med. 148:548, 1978) & Am.
J. Gastroent. 89:1071, 1994.(CP-96-13)
- Clinical Chemistry vol. 18, Oct. 1972.
- Batts KP, et. al. Histologic Changes Mimicking Biliary Disease
in Liver Biopsies With Venous Outflow Impairment, Modern Pathology
17(7):874-878, July 2004.
lab tests, Practice Guidelines, National Academy of Clinical
Biochemistry (NACB), USA.
| (posted 5 July 2002; latest addition 2 May 2005)
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