Sorted By Test Name - Mayo Medical Laboratories

FRAG
9064
OSCAL
80579
dehydration, the urine osmolality should be three to four times the plasma osmolality.
Reference Values:
0-11 months: 50-750 mOsm/kg
> or =12 months: 150-1,150 mOsm/kg
Clinical References: Newman D, Price C: Renal Function and Nitrogen Metabolites. In Tietz
Textbook of Clinical Chemistry. 4th Edition. Edited by CA Burtis, ER Ashwood. Philadelphia, PA, WB
Saunders Company, 2006
Osmotic Fragility, Erythrocytes
Clinical Information: Spherocytes are osmotically fragile cells that rupture more easily in a
hypotonic solution than do normal RBCs. Because they have a low surface area: volume ratio, they lyse at
a higher osmolarity than do normal discocyte RBCs. Cells that have a larger surface area: volume ratio,
such as target cells or hypochromic cells are more resistant to lysing. After incubation, an increase in
hemolysis is seen in hereditary spherocytosis.
Useful For: Suspected hereditary spherocytic hemolytic anemia Confirming or detecting mild
spherocytosis
Interpretation: Increased lysis in 3 or more concentrations of sodium chloride indicates increased red
cell fragility.
Reference Values:
0.50 g/dL NaCl (unincubated)
Males: 0.0-47.8% hemolysis
Females: 0.0-31.1% hemolysis
0.60 g/dL NaCl (incubated)
Males: 18.7-67.4% hemolysis
Females: 10.9-65.5% hemolysis
0.65 g/dL NaCl (incubated)
Males: 4.4-36.6% hemolysis
Females: 0.2-39.3% hemolysis
0.75 g/dL NaCl (incubated)
Males: 0.8-9.1% hemolysis
Females: 0.0-10.9% hemolysis
Clinical References: Palek J, Jarolin P: Hereditary spherocytosis. In Hematology. 4th edition.
Edited by WJ Williams, E Beutler, AJ Erslev, MA Lichtman. New York, McGraw-Hill Book Company,
1990, pp 558-569
Osteocalcin, Serum
Clinical Information: Osteocalcin, the most important noncollagen protein in bone matrix, accounts
for approximately 1% of the total protein in human bone. It is a 49-amino acid protein with a molecular
weight of approximately 5800 daltons. Osteocalcin contains up to 3 gamma-carboxyglutamic acid
residues as a result of posttranslational, vitamin K-dependent enzymatic carboxylation. Its production is
dependent upon vitamin K and is stimulated by 1,25 dihydroxy vitamin D. Osteocalcin is produced by
osteoblasts and is widely accepted as a marker of bone osteoblastic activity. Osteocalcin, incorporated
into the bone matrix, is released into the circulation from the matrix during bone resorption and, hence, is
considered a marker of bone turnover, rather than a specific marker of bone formation. Osteocalcin levels
are increased in metabolic bone diseases with increased bone or osteoid formation including osteoporosis,
osteomalacia, rickets, hyperparathyroidism, renal osteodystrophy, thyrotoxicosis, and in individuals with
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