ADVIA Chemistry Systems Cholinesterase Assay

The steadily growing menu of the ADVIA® 1650 has a new addition, Cholinesterase.

Clinical significance:

Cholinesterase levels in serum are useful as a test for liver function, as an indicator of possible insecticide poisoning or for the detection of patients with atypical forms of the enzyme
A 30% to 50% decrease in levels is observed with acute hepatitis and in chronic hepatitis of long duration. Decreases are also seen with advanced cirrhosis and carcinoma with metastasis to the liver
Normal range = 17 +/- 4 U/L

Intended use:

The ADVIA Cholinesterase assay is an in-vitro diagnostic device intended to measure cholinesterase enzyme activity in human serum and plasma (lithium heparin) on the ADVIA chemistry systems.

Summary and explanation:

This cholinesterase method is based on the method of Knedal and Bottger.

Principles of the procedure:

Cholinesterase catalyzes the hydrolysis of butyrylthiocholine to butyrate and thiocholine; the latter reduces 5,5'-dithiobis(2-nitrobenzoic acid) to 5-thio-2-nitrobenzoate. The increase in absorbance at 410 nm is proportional to the cholinesterase activity in the sample.

Reagents:

The reagents are provided in the package size as listed below. Components of the package are available as a kit only.

Prod. No.	Contains	Amount (mL)	# of Tests
B01-4605-01	Cholinesterase Reagents	R1: 4 x 205	4 x 133
		R2: 4 x 115	4 x 133

Expected values:

The expected values for this method are 4,900 U/L to 11,900 U/L. This range is provided for reference only. As with all diagnostics tests, each laboratory should establish its own normal range.

Imprecision:

Data were collected on two (2) ADVIA 1650 chemistry systems. Imprecision estimates were obtained on commercially available control materials. Each sample was assayed two (2) times per run, one or two runs, for least 16 days. Imprecision estimates were computed according to NCCLS document EP5-A, Evaluation of Precision Performance of Clinical Chemistry Devices; Approved Guideline.

		Total	Within-run
Specimen Type	Level	SD	CV(%)
Serum Control 1	4236	47.0	1.1
Serum Control 2	4686	54.9	1.2

Analytical range:

This method is linear from 1,500 U/L to 30,000 U/L for serum and plasma.