Alkaline Phosphatase Isoenzymes (Sendout)

Interpretation

Method

Total Alkaline Phosphatase: Colorimetric

Alkaline phosphatase Isoenzymes: Electrophoresis

Reference Range

See individual components

Ref. Range Notes

Reference Values:

Alkaline Phosphatase:

Males:

Age:	Reference Value:
0-14 days:	83-248 U/L
15 days-<1 year:	122-469 U/L
1-<10 years:	142-335 U/L
10-<13 years:	129-417 U/L
13-<15 years:	116-468 U/L
15-<17 years:	82-331 U/L
17-<19 years:	55-149 U/L
> or =19 years:	40-129 U/L

Females:

Age:	Reference Value:
0-14 days:	83-248 U/L
15 days-<1 year:	122-469 U/L
1-<10 years:	142-335 U/L
10-<13 years:	129-417 U/L
13-<15 years:	57-254 U/L
15-<17 years:	50-117 U/L
> or =17 years:	35-104 U/L

Alkaline Phosphatase Isoenzymes:

Age: < or =17 years: Reference values have not been established for patients less than 18 years of age.

Age > or =18 years:

ALP Isoenzyme:	Reference Value:
Liver %:	30.2-74.7 %
Liver U/L:	15.8-71.9 U/L
Bone %:	23.8-68.3 %
Bone U/L:	12.0-56.7 U/L
Intestine %:	< or =22.5 %
Intestine U/L:	< or =12.6 U/L

Interpretation:

Liver alkaline phosphatase (ALP) isoenzyme is most frequently elevated when total ALP is elevated. Increased liver ALP is associated with a wide group of conditions including acute hepatitis, cirrhosis, fatty liver, drug induced liver disease, obstruction of biliary flow, bile duct stricture, primary biliary cirrhosis, and metastatic carcinoma of the liver.

Bone ALP is elevated due to increased osteoblastic activity. Abnormally elevated bone ALP may be indicative of bone tumors, Paget’s disease, or renal rickets.

Intestinal ALP is detectable in approximately 20% of samples tested. Intestinal ALP is most frequently noted postprandially in patients with blood group O or B.

Interferences and Limitations

Alkaline phosphatase (ALP) Isoenzyme:

• High concentrations of phosphate, oxalate, citrate, and cyanide will inhibit ALP activity.
• Excess glycine may inhibit ALP activity by complexing magnesium.
• Patients should be fasting. Patients may have an elevated intestinal ALP about two hours after a fatty meal.

References

• Mayo Clinical & Interpretive Information: Alkaline Phosphatase, Total and Isoenzymes, Serum

Ordering & Collection

Specimen Type

Blood

Collection

6 mL blood in GOLD SST or RED TOP tube

Patient Preparation: Patient should be fasting for 8 hours.

Handling Instructions

Outside Laboratories:

• Centrifuge sample within two hours of collection and aliquot serum into a separate plastic vial.
• Serum from red tops should be immediately aliquoted; serum from gold top tubes may remain on the gel, refrigerated, for up to 7 days prior to being transferred.
• Once transferred, freeze serum at -20°C while awaiting shipment. Transport on dry ice.

Stability: Frozen (Preferred): 14 days; Refrigerated: 7 days; Ambient: 7 days.

Reject Due To: Gross hemolysis or icterus. Gross lipemia is acceptable.

Quantity

Requested: 1 mL serum
Minimum: 1 mL serum

Processing

Receiving Instructions

• Centrifuge sample within two hours of collection.
  • Serum from red tops should be immediately aliquoted; serum from gold top tubes may remain on the gel, refrigerated, for up to 7 days prior to being transferred.
• Aliquot serum into a separate plastic vial, leaving room for expansion at the top, and freeze at -20°C.

Sendouts:

• Order Mayo Test: ALKP
• Interfaced: Yes [Interface: 601; Worksheet: MAFZ]

Stability: Frozen (Preferred): 14 days; Refrigerated: 7 days; Ambient: 7 days.

Reject Due To: Gross hemolysis or icterus. Gross lipemia is acceptable.

Misc Sendout

Performance

Lab Department

Sendouts Mayo Lab (FZ)(MAFZ)

Frequency

Performed: Tuesday through Saturday. Report Available: 3-5 days from sample receipt at Mayo Clinic Labs.

Available STAT?

No

Performing Location(s)

Sendout	Mayo Clinic Laboratories 800-533-1710 200 First Street Southwest Rochester, MN 55901

Billing & Coding

CPT Codes

84075, 84080

LOINC

6768-6

Interfaced Order Code

UOW5713