Alkaline Phosphatase, Total (ALP), Plasma / Fluid

 

Specimen requirement

Adult patient:

 

 Heparin gel tube

 

Minimum blood volume: 5 mL

Spot fluid:

Plain bottle

Minimum volume: 10 mL

 

Paediatric patient:

Paediatric heparin tube

Number of vials: 1

Minimum blood volume: 1.3 mL

Authorisation code required

No

No

24 Hr available service

Yes

 

(Call extension: 3353 for express result)

No

Method

Spectrophotometry

Reference interval

 

Male Low High Female Low High Unit Source
Age 0 - 5 130 380 Age 0 - 5 130 330 U/L Clin Chem 1983
Age 6 - 12 160 478 Age 6 - 9 134 389 U/L Local population study in 2008
Age 13 - 16 81 447 Age 10  - 13 77 388 U/L
Age 17 - 18 43 207 Age 14  - 18 45 173 U/L
Age > 19 43 105 Age 19 - 50 33 84 U/L
      Age 51 - 55 30 90 U/L Clin Chem 1983
      Age > 55 45 145 U/L

 

(Source:

1. From local population study in 2008

2. Francoise Schiele, Joseph Hanny, Joelle Hitz et al. Total Bone and Liver Alkaline Phosphatases in plasma: Biological Variations and Reference Limits. Clin Chem 1983; 29: 634 - 41)

Female during pregnancy:
13 - 20 weeks 40 - 92 U/L
21 - 28 weeks 44 - 119 U/L
29 - 34 weeks 56 - 159 U/L
35 - 42 weeks 88 - 269 U/L
During active labour 109 - 368 U/L
Day 1 postpartum 96 - 280 U/L
Day 2 postpartum
89 - 257 U/L

(Source: Klajnbard A et al. Laboratory Reference Intervals during Pregnancy, Delivery and the Early Postpartum Period.  Clin Chem Lab Med. 2010 Feb; 48(2): 237 - 48.)

Clinical indication

Investigation of hepatobiliary or bone disease

Result interpretation

Increased levels in liver disease (particularly in association with cholestasis), bone disease (with increased osteoblastic activity, e.g. Paget’s disease), some bony metastases (especially prostate and breast), and at times in malignancy without liver or bone metastases (Regan isoenzyme)

 

May also be elevated in some gastrointestinal diseases or due to a macroenzyme.

 

Alkaline phosphatase isoenzymes (bone-specific alkaline phosphatase) are rarely necessary to identify the source of an elevated ALP.

 

Marked but transient elevation of ALP may be seen in children, probably attributable to viral infection.

 

Abnormal dentition and fragile bones with decreased ALP characterise the autosomal recessive disease hypophosphatasia.

 

EDTA when present chelates Ca2+ and Mg2+ and thus inactivates the ALP activity.

Measurement of uncertainty

See table.

Frequency of measurement

Daily