Chemiluminescent determination of leukocyte alkaline phosphatase: an advantageous alternative to the cytochemical assay

The determination of leukocyte alkaline phosphatase (LAP) is used as an aid to diagnose many diseases in the laboratory. For example, it can be used to distinguish chronic myeloid leukemia (CML) from other myeloproliferative disorders (particularly myelofibrosis and polycythemia) and leukemoid react...

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Bibliographic Details
Published in:Journal of clinical laboratory analysis 2007, Vol.21 (2), p.91-96
Main Authors: Kanegae, Marília P.P., Ximenes, Valdecir F., Falcão, Roberto P., Colturato, Virgílio A.R., de Mattos, Éderson R., Brunetti, Iguatemy L., da Fonseca, Luiz Marcos
Format: Article
Language:English
Subjects:
Adamantane - analogs & derivatives
Adamantane - chemistry
Alkaline Phosphatase - analysis
Alkaline Phosphatase - chemistry
chemiluminescence
chronic myeloid leukemia
Histocytochemistry - methods
Humans
Immulite® (AMPPD)
Indicators and Reagents - chemistry
Leukemia, Myelogenous, Chronic, BCR-ABL Positive - blood
Leukemia, Myelogenous, Chronic, BCR-ABL Positive - diagnosis
Leukemoid Reaction - blood
Leukemoid Reaction - diagnosis
leukemoid reactions
leukocyte alkaline phosphatase
Luminescence
Luminescent Measurements
Neutrophils - chemistry
Neutrophils - enzymology
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Summary:The determination of leukocyte alkaline phosphatase (LAP) is used as an aid to diagnose many diseases in the laboratory. For example, it can be used to distinguish chronic myeloid leukemia (CML) from other myeloproliferative disorders (particularly myelofibrosis and polycythemia) and leukemoid reactions (LR). Traditionally, this test is performed with the use of subjective cytochemical assays that assign a score to the level of LAP. Here we present a nonsubjective, quantitative, sensitive, and inexpensive chemiluminescent technique that determines LAP based on the commercial reagent Immulite® (AMPPD). To validate this methodology, intact leukocytes obtained from 32 healthy subjects, nine CML patients, and nine LR patients were submitted to the optimized protocol. By measuring the light emission elicited by four concentrations of neutrophils, we were able to estimate the activity of LAP per cell (the slope of the curve obtained by linear regression). A high linear correlation was found between the chemiluminescent result (slope) and the cytochemical score. The slope for healthy individuals ranged between 0.61 and 8.49 (10–5 mV.s/cell), with a median of 2.04 (10–5 mV.s/cell). These results were statistically different from those of CML patients (range=0.07–1.75, median=0.79) and LR patients (range= 3.84–47.24, median=9.58; P
ISSN:0887-8013
1098-2825
DOI:10.1002/jcla.20140