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Latex allergen testing with FITkit®

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Latex allergen testing with FITkit® service

FITkit® is an ELISA test for measuring natural rubber latex (NRL) allergens from a variety of rubber products, such as gloves, condoms, teats, etc. FITkit® technology has been developed by the leading scientists working in the field of NRL allergy, in cooperation with major glove manufacturers.

It shows a good correlation to the allergen content of gloves, measured by currently available patient IgE methods.

This novel method is the first ever test for the measurement of clinically relevant NRL allergens, and enables quantification of individual allergens.

It overcomes the significant limitations of other tests by using highly purified and characterized allergens, and specific monoclonal antibodies, against four major latex allergens (Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02) known to be present in NRL products. A separate FITkit® is available for measuring each of the major allergens. FITkit® technology is compliant with ASTM International standard D7427-16.

The advantages of FITkit® are:

  • Direct measurement of the relevant allergens individually;
  • Unique sensitivity;
  • Consistent and reliable results;
  • Convenient procedure and short assay time (< 2 hours);
  • No interference from other substances.

Possible applications for the FITkit test vary, based on the R&D or quality control needs of producers to measure latex allergens in finished products or in different phases along the production line, to assessing production development as a type of quality control criteria in the different distribution organizations of purchasing departments.​

A newer approach has found the FITkit applicable for use in synthetic product contamination control. If the absence of major NRL allergens in synthetic protective gloves or in other synthetic rubber products with a medical use requires verification, use of the FITkit offers a useful solution.​


1 Peixinho C et alLatex allergy: new insights to explain different sensitization profiles in different risk groups.Br J Dermatol. 2008 Jul;159(1):132-6. doi: 10.1111/j.1365-2133.2008.08614.x.

2 Kang PB et al. The immuno cross-reactivity of gutta percha points. Dent Mater. 2007 Mar;23(3):380-4


Icosagen is member in ASTM International,
the American Society for Testing and Materials (ASTM).

Latex allergy

Over the last 20 years, natural rubber latex (NRL) allergy has become a serious worldwide health problem. Up to 17% of healthcare workers and about 1% of the general population are allergic to natural rubber latex.

While contact urticaria is the most common clinical manifestation of NRL allergy, the disease may present in its most serious form as anaphylaxis, a life threatening systemic reaction. NRL based medical devices (gloves, masks, etc.) are a potential source of sensitization to both healthcare personnel and patients. Potentially, anyone in contact with objects containing NRL (e.g. gloves, condoms, catheters, dental dams, balloons, toys, etc.) can become sensitized. On the other hand, there are several risks (HIV, etc.) threatening healthcare workers, and the reason for using medical devices is unavoidable. A long list of the latex products are in daily use.

Natural rubber latex allergens

Liquid latex from the rubber tree, Hevea brasiliensis, is the source of NRL and contains over 200 proteins; 14 have been identified as allergens. Only some of allergens retain their allergenic properties through the manufacturing processes.

Thus, when trying to reduce the allergen content of NRL products, any good testing method must measure all components with clinical relevance present in the final product. The NRL allergens that have been shown to be clinically relevant to genuine NRL allergy, and present in the final NRL products with maintained allergenicity are Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02. According to the latest studies, quantification of these four major allergens shows the allergenic potential of rubber products.


1 Turjanmaa, K. et al., Allergy 51 (1996) 593 – 602;

2 Liss, G. M. and Sussman, G. L., Am. J. Ind. Med. 35 (1999) 196 –200

3 Poley Jr, G. E. and Slater, J. E., J. Allergy Clin. Immunol. 105 (1997) 1054 – 1062

4 Palosuo, T. Alenius, H. Turjanmaa, K: Quantification of Latex Allergens. Methods 27 2002; 52-58

5 Palosuo, T. et al, Latex allergy: the sum quantity of four major allergens shows the allergenic potential of medical gloves. Allergy, 2007, 62:781-786

6 International Union of Immunological Societies allergens list:  (Home> Plantae magnoliopsida > Malphigales > Hevea brasiliensis) 

FITkit® as a tool in risk management

Why do we need the latex allergen measurement tests (FITkit, ASTM D7427) at all?

The history of natural rubber latex (NRL) as the prime source of glove material, with its excellent barrier and other properties, is well known. Furthermore, a review of literature reveals that NRL gloves, when compared with alternatives, tend to be stronger, more flexible and preferred by some clinicians. On a daily basis, many other latex products are utilised in healthcare and by consumers; however, NRL gloves have been under pressure for more than 20 years due to the risk of allergies. Improvements in glove manufacturing and more extensive use of synthetic gloves have led to a marked decrease in allergy cases in developed countries in Europe and North America. Notwithstanding this diminishing trend, the risk of allergy continues to be considered in every hospital’s risk management policy. In order to assess the source of potential sensitization (a glove for instance), we need a tool for assessment. Since the total protein (ASTM 5712) or antigenic protein (ASTM 6499) assays do not provide definitive data for the presence of allergenic proteins, the FITkit or ASTM D7427 are the only currently available methods to directly provide this information. Specific allergen measurement is considered the best option to assess potential risks of medical gloves (REF 1). A number of scientific reports reveal that rubber products fulfilling the requirements for total protein (< 50 µg/g) or antigenic protein (<10 µg/g) can still contain clearly significant concentrations of allergenic latex proteins (REF 2-6). Therefore, data on the allergen content of gloves should be made available, and gloves with high allergen content (sum quantity of four major allergens over 1.15 µg/g, (REF 7)) should not be recommended.

What is the difference between ASTM D7427 and FITkit?

ASTM D7427-16 is an ASTM standard, defining properties of a generic test that allows for the reliable measurement of clinically relevant latex allergens, Hev b 1, 3, 5 and 6.02, respectfully. ASTM has made available Industry Reference Materials and guides via D7427 standard text, allowing everyone interested to create their own assay. FITkit is a commercially available test that is compliant with ASTM D7427. FITkit is available as ready-to-use test reagents or a testing service. 

Impact of FITkit data on the quality of risk management

FITkit test data helps to reliably differentiate gloves (or any other latex products) with proven low allergen content from others. Furthermore, available information about the allergen content of latex gloves raises the credibility of the producer’s or distributor’s statement about glove properties. Logically, it will significantly improve users’ ability to choose low allergen content gloves. This practice, on the other hand, will reduce the use of high allergen content gloves and, in turn, lead to a decrease in the exposure of people to latex allergens. There are available reports revealing whether gloves contain less than 0.15 µg/g (FITkit detection) of clinically relevant allergens, making it more than likely that they can be used safely. Furthermore, products that contain such small amounts of the studied natural rubber allergens are very likely suitable for a significant number of sensitized users, and the use of these gloves is not likely to create a risk in most persons unaware of their allergy (REF 8, 9).

How can one be sure that the use of high quality protective gloves poses a minimal but acceptable risk for latex sensitive users?

Available guidelines typically recommend choosing synthetic alternatives instead of NRL gloves for sensitised users. At the same time there has been a search by manufacturers and health authorities for a methodology that would allow for confirmation that synthetic products are free of NRL. The latex-free definition is becoming more complicated, as it is usually based only on a manufacturer’s announcement, not on reliable test results. Synthetic gloves are recommended as safer alternatives, because they, by definition, do not contain NRL proteins. A recent publication by M. Angeles Gonzalo Garijo, et al. (REF 10) on NRL contaminated nitrile gloves in healthcare shows that this is sometimes not true. In this respect, to fulfil a recommendation of being safer alternatives, synthetic gloves should be verifiably clean of NRL, i.e. undergo periodic control. Currently, FITkit or D7427 would be a suitable method to convincingly demonstrate the absence of the four major NRL allergens in gloves or other rubber products, when the need for such a statement emerges.

How gloves with proven low allergen content influence public safety?

Knowledge of the allergen content of available gloves will significantly improve users’ ability to choose low allergen content gloves. This practice, on the other hand, will reduce the use of high allergen content gloves and, in turn, lead to a decrease in the exposure of people to latex allergens. Eventually this development could have a marked public health impact by further reducing the incidence of new cases of latex allergy. Limitations in predictability of sensitization to NRL and resulting allergic reactions should not preclude attempts to overcome the problems associated with assessing potential exposure risks to products containing NRL allergens. Latex allergen measurement is one of the specific tools available for overcoming latex allergy concerns.


1 Tomazic-Jezic, V. et al. Performance of Methods for the Measurement of Natural Rubber Latex (NRL) Proteins, Antigens and Allergens. J Allergy Clin Immunol 2004:113:S211 

2Kostyal, D. et al. Latex as a significant source of Hevea brasiliensis allergen exposure. Ann Allergy 2009 

3 Yagami, A. et al. Hev b 6.02 is the most important allergen in HCW Sensitized Occupationally by NRL gloves. Allergology International 2009; 58:347-355 

4 Mabe, D.O. et al. Allergenicity of latex rubber products used in South African dental schools. S Afr Med J 2009; 672-674. 

5 Mok, K.L. Immunological Measurement of Four Major Allergens in Natural Rubber Latex Medical Gloves. 5th International Rubber Glove Conference 2010 paper

6 Koh, D.  et al. A study of natural rubber latex allergens in gloves used by healthcare workers in Singapore British Journal of Dermatology 2005 153, pp954–959 

7 Palosuo, T. et al. Latex allergy: the sum quantity of four major allergens shows the allergenic potential of medical gloves. Allergy 2007; 62:781-6. 

8 Turjanmaa, K, Kanto, M., Kautiainen, H., Reunala, T., Palosuo, T. Long-term outcome of 160 adult patients with natural rubber latex allergy. J Allergy Clin Immunol 2002; 110:S70-4. 

9 Glove study 2005. Finnish National Agency for Medicines, 

10 Gonzalo Garijo M. A. et al. Hypersensitivity reactions due to nitrile gloves, J Allergy Clin Immunol 2011

FITkit® ELISA kits​

FITkit® products are four separate ready-to-use test reagent kits, Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02, accordingly, and their components. Each kit contains all reagents ready to use for testing 41 duplicate samples.



Product name

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Material Safety Data Sheets

Also are available all single components of FITkit®.

Send your orders and inquiries to:

Please forward all your technical questions to:

Storage conditions (to complement chapter 5. Storage conditions, page 5 in FITkit user manuals):

Shipping temperature of the kit is +2…+25 °C (short time storage up to 7 days).
Storage temperature of the kit is +2…+8 °C (long time storage).

Latex allergen testing service​

Icosagen AS is pleased to offer latex allergen testing service. The latex allergen content of your samples will be measured by FITkit® Hev b1, FITkit® Hev b3, FITkit® Hev b5 and FITkit® Hev b6.02 tests. The prices include testing of all 4 allergens. The prices exclude VAT.

Service code

Service name

Lead time

(starting from the date
when the samples have arrived)

Price per sample

1 S3-350-100

FITkit testing service

2 weeks

138 €

2 S3-350-200

FITkit EXPRESS testing service

1 week

279 €

3 S3-350-300*

FITkit SPECIAL EXPRESS testing service

max. 3 business days

391 €

4 S3-350-001**

FITkit testing service sample handling fee

50 €

* Sometimes our customers need the results as soon as possible, which is why we are also offering FITkit SPECIAL EXPRESS service. However, the possibility exists that we may not always be able to provide this service. Therefore, we suggest inquiring in advance about availability.

** A sample handling fee that is added to the service price per sample. This fee isn’t added to glove and condom samples.

Instructions for sending the samples:​

Please pack each sample in a separate pouch, making sure that different samples do not come in contact with each other. Also, include the names of the samples exactly as you wish them to appear on the certificates. 
Note: In the event that you are sending a branded product for testing and you would like to see the brand name of that tested item on the certificate, the product must be in its original package. The package must be unopened. 

For testing, we technically need about 3 g of material. Though we always request 5-10 times more be sent, in order to be able to repeat the testing, if we encounter any surprises.

Another viewpoint is distribution of latex allergen content in your item(s). If you do not have any previous information about the allergen content of your product(s), we recommend that you send us samples from three different batches and test them as separate samples. 

Send the samples, together with your contact information and invoicing address, to:

Icosagen AS (FITkit testing)
Attn: Maia-Liisa Voolaid
Eerika tee 1
Õssu, Kambja vald
Tartu maakond 61713

Please attach the delivery note to your shipment. If you don’t have your own delivery note, then you can use our delivery note template — Delivery Note

Should you have any questions regarding this service or pricing, please do not hesitate to contact us at or by phone: +372 737 7045.

Please forward all your technical questions to:

Frequently asked questions​

Why it is not enough to measure the total protein level?

Only some of the proteins are allergenic; total protein content does not yield reliable information about the allergenicity of a product.

Why it is not enough to measure only one allergen?

Patients can be sensitised to one or more allergens; different gloves and other NRL products can contain different allergens.

Are all proteins and antigens from the rubber tree equally allergenic?​

No. During the rubber manufacturing process many of the proteins degrade, denature and lose their activity, however, some proteins retain their allergenic properties throughout the process. Latex products can have high protein but low allergen levels and vice versa.

Why have we chosen Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 to be included in the kits?​

According to the current literature, these four allergens are the ones that have been unequivocally demonstrated to be present in glove extracts and to resist the glove-manufacturing process.[1]

Please forward all your technical questions to:

Our locations

United States Office

77 Geary St. 5th Floor
San Francisco, CA 94108
+1 415 548 6625

European Office

Eerika tee 1
Õssu, Kambja vald
Tartu maakond 61713
+372 737 7070
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