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NY N010383

May 8, 2007



TARIFF NO.: 3002.10.0190

Mr. Rex Spent
Associate Director
Pfizer, Inc.
700 Chesterfield Parkway West
Chesterfield, MO 63026

RE: The tariff classification of a solid phase enzyme-linked immunosorbent assay (ELISA) for the estimation of rat or mouse Glutathione S-Transferases in biological fluids, in kit form, from Ireland

Dear Mr. Spent:

In your letter dated April 25, 2007, you requested a tariff classification ruling.

The prospective product is described as an in vitro enzyme-linked immunosorbent assay (ELISA) kit for estimating rat or mouse Glutathione S-Transferases (GSTs) activity in biological fluids. GSTs are a group of enzymes that play a significant role in cell detoxification. While you submitted no protocol or technical literature, we believe that this assay will be utilized for quantitative estimation of GSTs as an indicator of hepatic or renal injury. You describe the kit as consisting of the following: 1) Microassay Wells coated with rabbit polyclonal Immunoglobulin (Ig)G antibody directed against rat α945 GST; 2)Microassay Strip Holder; 3) Plate Cover; 4) Enzyme Conjugate- rabbit anti-rat α945 GST polyclonal IgG; 5) Purified α945 GST in 50% glycerol as a calibrator concentrate; 6) Purified α945 GST in 55% glycerol as a positive control; 7) Rat Urine stabilizing buffer; 8) Sample Diluent containing thimerosal and sodium azide; 9) Wash Concentrate 25x tris buffered saline/Tween 20; 10) Reduction Substrate Solution, namely, stabilized TMB (Tetramethylbenzidene dihydrochloride); 11) Stop Solution 1N sulphuric acid.

In general, an ELISA is an immunochemical test involving an enzyme, plus an antibody (or antigen). Enzyme-linked immunosorbent assays are used to detect substances that have antigenic properties (e.g., proteins, hormones, bacterial antigens and antibodies). Basically, an ELISA consists of a solid surface, such as a plate containing depressions or “wells,” onto which an antibody having an affinity for a “target” substance (see above) is coated. A mixture consisting of a) purified target substance coupled to an enzyme, and b) the actual test specimen is added to the test system. If no target substance is present in the test specimen, then only the enzyme-linked purified target substance will bind to the antibody coated on the surface of the wells. Therefore, the more “target” present in the test specimen, the less enzyme-linked purified target substance will be bound. A substance (e.g., TMB- Tetramethylbenzidine dihydrochloride) the enzyme acts on is then added, and the amount of the product produced by the enzyme-catalyzed reaction is measured, such as by the change produced in the color of the solution. The resulting color change is indicative of the level of the target substance found in the test specimen.

The test procedure of the subject kit would be based on the sequential addition of specimen sample, antibody-enzyme conjugate and substrate to the microassay wells coated with rabbit polyclonal Immunoglobulin (Ig)G antibody directed against rat α945 GST. The reagent that governs the specificity of the test in the described kit is an antibody conjugate, specifically an enzyme-antibody conjugate, a product encompassed by heading 30.02, HTSUS. Explanatory Note 30.02(C)(2)(c), HTSUS. In our opinion, the antibody-conjugate reagent imparts the essential character to the kit. Explanatory Note 30.02(E).

Pursuant to Harmonized System Explanatory Note 38.22, HTSUS, and Harmonized System Explanatory Notes 30.02(C) and (E), HTSUS, the applicable subheading for the subject product will be 3002.10.0190, Harmonized Tariff Schedule of the United States (HTSUS), which provides for “Antisera and other blood fractions and modified immunological products, whether or not obtained by means of biotechnological processes: Other.” The rate of duty will be free.

This merchandise may be subject to the rules and regulations of the U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, located at 1600 Clifton Rd., Atlanta, GA 30333. You may contact them, by telephone, at: 404) 639-3534 / (800) 311-3435.

Duty rates are provided for your convenience and are subject to change. The text of the most recent HTSUS and the accompanying duty rates are provided on World Wide Web at http://www.usitc.gov/tata/hts/.

This ruling is being issued under the provisions of Part 177 of the Customs Regulations (19 C.F.R. 177).

A copy of the ruling or the control number indicated above should be provided with the entry documents filed at the time this merchandise is imported. If you have any questions regarding the ruling, contact National Import Specialist Harvey Kuperstein at 646-733-3033.


Robert B. Swierupski

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