|
||||||
|
|
|
 |
NEWS & INFORMATION |
|
Source To Surgery - February 1995, Vol. 3 Issue I
Kristiina Turianmaa. MD. Deputy Chief Physician,
Skin Prick Testing (SPT)The SPT Tests Available for Diagnosis article for details) can be used with known latex allergic patients. SPT is the most sensitive for comparing allergenicity of different products (especially surgical and exam gloves) but requires NRL sensitized people who are willing to be retested. This study requires the permission of the hospital ethics committee and informed consent of the patient. When only a slight or no reaction occurs in the group of patients tested, it is probable that the product will not sensitize and is therefore safe for general use.The SPT results correlate well with the RAST Inhibition and ELISA Inhibition methods. RAST Inhibition (RI)The advantage of this method in comparison to SPT is that only sera from NRL sensitized humans is required.The values used in this test are given in arbitrary units which means everything is compared to the value set for NRL. So far this method cannot be used for worldwide standardization because a standardized NRL allergen as well as a standardized serum pool needs to be used by all testing laboratories. The same disadvantages prevent it from being used commercially. It is also a time consuming and expensive test to do. In spite of these difficulties, it has been shown that with different NRL samples and different serum samples a good correlation exists between various laboratories using this method. For example, the results obtained by the Mayo Clinic (Yunginger) and the Finnish Latex Research Group (Soili Makinen-Kiljunen) will rank gloves in the same order of allergenicity (unpublished). ELISA Inhibition (EI)ELISA inhibition is a well known test methodology. The Finnish Latex Research Group has developed this technique for the analysis of NRL allergens. The results obtained to date show this method to correlate very well with SPT and RI (unpublished). This method also uses human sera from NRL sensitized individuals which means it has the same limitations as RI.Total Protein DeterminationIn NRL there are over 240 different proteins and polypeptides of which 57 have so far been identified as allergens. In addition to genuine NRL proteins, other proteins such as casein may be added during manufacturing.A preferred method for total protein measurement, and recommended by the FDA, is the modified Lowry. This is a chemical method which has some drawbacks such as lack of sensitivity, specificity and interferences from accelerators and other additives used in glove manufacture. It has been shown that correlation between SPT and the modified Lowry is relatively good.* Therefore, this method can be used as a primary check by manufacturers to determine the protein amounts of their products. Latex ELlSA for Antigenic Proteins (LEAP) AssayThe LEAP Assay (available commercially) relies on the use of antibodies developed in rabbits against ammoniated latex proteins. Therefore, it is basically a total protein assay and is not allergen specific.For the time being, the LEAP assay has not been validated against specific allergen measuring methods, such as SPT or RAST Inhibition.
*Esah Yip, K Turjanmaa, K.P. Ng and K.L. Mok: Allergic
responses and levels of extractable proteins In NR latex gloves and dry
rubber products. J. nat. Rubb. Res., 9(2), 79-86, 1994.
|
| BACK TO TOP |
 |
| Home | About Ansell | Gloves | News & Information | What's New! | Privacy Notice |