SAMPLING
BROTHERS
Dr Sebastian Klaus and Dr Marion Nies describe a rapid fi eld test for detecting organophosphate poisoning in whole blood
The newly available CE certifi ed cholinesterase (ChE) IVD device, ChE Check Mobile, provides an important diagnostic capability that allows rapid and accurate determination of acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) activity in whole blood. The device can be used in both permanent medical treatment facilities and under fi eld conditions, in particular during deployed fi eld operations when exposure to organophosphates (OPs) such as nerve agents is suspected. Even in cases of weak or unspecifi c symptoms, the ChE check mobile
is small and easy to use, and enables medical offi cers in charge to establish rapid and accurate diagnosis and to provide timely and adequate antidote therapy. The practical test device allows precise and reproducible determination of AChE and BChE activity within four minutes at ambient temperatures of 10°C to 50°C. The simple test procedure requires only a few menu-driven operations and the interpretation of test results is supported by supplemental information and instruction; thus, enabling the test execution aſt er short training.
Eff ects of OP Irreversible inhibition of the pivotal enzyme acetyl cholinesterase is the predominant toxic eff ect of many organophosphorus compounds and carbamates (organic compounds derived from carbamic acid). Many OPs and carbamates are still being used worldwide as agricultural pesticides, while some have been incorporated into and abused as CWAs (chemical warfare agents). Inhibition of AChE by OP results in accumulation of acetylcholine in the synaptic cleſt (the microscopic gap between neurons) of cholinergic- innervated tissues, making many body organs dysfunctional and ultimately resulting in death by central and peripheral respiratory failure.
Need for a rapid test Until now, evaluation of clinical symptoms has been the only possibility for on-site diagnosis of OP poisoning because there were no fi eld devices available for rapid and precise on-site determination. Particularly in cases when symptoms were weak or unspecifi c, a clinical laboratory confi rmation using complex, expensive and time-consuming analytical methods such as GC-MS (gas chromatography/mass spectrometry) became inevitable. As a result, lack of prompt diagnosis did not allow a timely and adequate antidote therapy. For this reason, ChE Check Mobile was developed by Securetec Detektions- Systeme AG (Brunnthal, Germany) in close co-operation with the Bundeswehr Institute of Pharmacology and Toxicology (Munich, Germany).
FIGURE 1: Components of the ChE Check Mobile
32 CBNW 2013/01
Method and device The determination of AChE and BChE in whole blood samples is based on the well-known Ellmann method used since 1961. The Ellman reagent forms a yellow colour which is measured by a photometer. The rate of colour formation
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