Acid Phosphatase (ACP)
Assay for the Quantitative Determination of Total & Prostatic
Activity Levels
Introduction
Phosphatases with
optimal activity below a pH of 7.0 are collectively referred to as Acid
Phosphatases (ACP). The greatest levels of ACP activity are present in
the liver, spleen, milk, erythrocytes, platelets, bone marrow and
prostate gland. As such, determination of the prostatic fraction of ACP
is of clinical interest as a biomarker in the detection, staging and
monitoring of carcinoma of the prostate. Elevations of ACP occur in
approximately 60% of men with prostate cancer, where the highest levels
are encountered in patients with metastic bone involvement. ACP produced
in the prostate is inhibited by tartrate, a property which is useful in
differentiating it from isoenzyme fractions originating elsewhere in the
body. More moderate elevations of ACP occur in Paget’s, Gaucher’s and
Niemann-Pick diseases, forms of hyperparathyroidism, assorted malignant
cancers with bone involvement (including female breast cancer), and
various hematological disorders. Additionally, as ACP is found in very
high concentrations in semen, its determination is useful in forensic
medicine applications and research.
Test Principle
Of the many methods
proposed for measuring ACP, the α-naphthylphosphate-Fast Red TR coupled
reaction, proposed by Hillman, is the most accepted. The DCL procedure
is based on this method, with L-tartrate used as the specific inhibitor
of the prostatic fraction. In the test reaction, ACP hydrolyzes α-naphthylphosphate
to yield α-naphthol, which reacts with the dye Fast Red TR to produce a
chromophore with strong absorbance at 405 nm. The rate of increase in
absorbance at 405 nm is proportional to the ACP activity of the sample.
If L-tartrate is added to the reagent, the prostatic fraction is
inhibited, but all other fractions in the serum react. Therefore, the
test is run both in the presence and absence of L-tartrate. The
difference in activity between the two assays is equal to the prostatic
ACP activity in serum.
Key
Features &
Benefits
All Inclusive
– Each test kit includes color reagent, inhibitor and stabilizing
solution to measure both prostatic and non-prostatic ACP activity in the
test sample.
Minimal Sample
Requirements
– Each assay requires only twenty (20) μL of sample, making it ideal for
geriatric testing.
Lengthy Stability Claims –
Each test kit features an eighteen (18) month shelf life, along with a
seven (7) day stability after reconstitution.
Flexible Testing
– Well suited for use with fully automated procedures, with an extensive
listing of instrument applications readily available.
Reliable Methodology – Fully
kinetic and widely accepted method demonstrates superior performance
characteristics with regard to linearity, accuracy, precision and
sensitivity.
Ideal for Research
Applications
– DCL’s ACP assay has a proven history of performance in a wide range of
research applications.
Convenient Packaging
– Offered in a convenient packaging format ideally suited for any
laboratory, regardless of workflow demands.
Specific Performance
Characteristics
Reportable Range
–- The reportable range of the assay using
automated procedures will depend on the sample to reagent ratio, as well
as other factors. However, for the majority of automated procedures,
the assay provides a reportable range of up to 40 U/L.
Accuracy
–- The performance of this method (y) was compared
with the performance of another commercially available method (x) on an
automated chemistry analyzer using fifty-four (54) samples ranging from
1.1 - 37.5 U/L. The correlation coefficient was 0.9976. This study
yielded a linear regression equation of y = 0.93x + 0.47 U/L.
Precision
–-
Precision estimates for Intra-Run performance were obtained on two (2)
separate levels of commercially available serum control materials with
acid phosphatase activity of 3.4 U/L and 21.1 U/L, a total of
twenty-five (25) times. The resulting SD’s were 0.11 U/L and 0.34 U/L
respectively, generating CV%’s of 3.2 and 1.6. Estimates for total
precision performance were obtained on two (2) separate levels of
commercially available serum control materials with activity of 3.7 U/L
and 28.5 U/L. The resulting SD’s were 0.24 U/L and 0.91 U/L
respectively, generating CV%’s of 6.5 and 3.2.
Ordering Information
|
Product
|
Catalogue Number
|
Packaging Configuration |
|
ACP
|
320-S3 |
10 x 10 mL
Color Reagent;
1 x 10 mL
Acetate Stabilizing Reagent;
1 x 2.5 mL
L-Tartrate Inhibitor |
|
Supporting Products
|
|
DC-Trol Level 1
Control |
SM-052 |
10 x 5 mL |
|
DC-Trol Level 2
Control |
SM-056 |
10 x 5 mL |
REFER TO PACKAGE INSERT AND/OR MSDS FOR ADDITIONAL TECHNICAL INFORMATION
Revision No. – 320.S3-10-04-06
©
Diagnostic Chemicals
Limited 2006. All rights reserved.
