The demand for devices aiding allergy diag­nosis is growing, reflecting the steadily rising number of allergy suf­ferers world­wide. Chil­dren are also showing symp­toms of aller­gies at an increas­ingly ear­lier age. This often includes colds and itching, but also headaches or asthma. This devel­op­ment is par­tic­u­larly no­ticeable in indus­trial regions such as Europe, the United States or Japan,” explains Magnus Askvid, Man­ager Pro­duc­tion Engi­neering at Thermo Fisher Sci­en­tific in Upp­sala, Sweden. He con­siders these regions the key mar­kets for the ImmunoCAP^TM assays, the company’s proven diag­nostic tool for decades.

„For us it was impor­tant to entrust a partner with the devel­op­ment of the machine, who can con­fi­dently respond to changing require­ments.”Magnus Askvid, Man­ager Pro­duc­tion Engi­neering at Thermo Fisher Scientific

An allergic reac­tion is always an over­reaction of the immune system to a cer­tain, often harm­less sub­stance that is rec­og­nized as for­eign. It then forms anti­bodies, so-called immunoglob­u­lins that can be detected with a CAP-test (car­rier-­polymer-system). With its quan­ti­ta­tive detec­tion of spe­cific immunoglob­u­line E (IgE), ImmunoCAP™ Spe­cific IgE makes it pos­sible to deter­mine sen­si­ti­za­tion at an early stage, often before clin­ical symp­toms have devel­oped in a patient. IgE detec­tion is nothing more than counting anti­bodies for a spe­cific allergen in the blood. “With ImmunoCAP^TM it is pos­sible to test sen­si­ti­za­tion to well over 500 dif­ferent aller­gens,” says Magnus Askvid.

The assembly system of the ImmunoCAP™ test dis­penser con­sists of inter­mit­tent machines.

The test principle

For the IgE test, the physi­cian takes blood from the patient’s vein or a cap­il­lary vessel. The obtained serum or plasma is added to the ImmunoCAP™ Allergen in a lab­o­ra­tory system and the number of the respec­tive anti­bodies is deter­mined. The result can con­firm or rule out allergen sen­si­ti­za­tion. An allergy diag­nosis is then made by the physi­cian, based on a detailed med­ical his­tory and fur­ther clin­ical exam­i­na­tions. “The mea­sure­ment of the IgE anti­bodies cir­cu­lating in the blood, how­ever, enables an objec­tive assess­ment of sen­si­tivity to an allergen and helps the physi­cian to pre­pare an allergen avoid­ance strategy and an indi­vidual treat­ment plan,” explains Magnus Askvid.

The caps are fed to an inter­mit­tently rotating turret, where the sponges are inserted.

The sponges are punched in par­allel from fleece soaked in IgE liquid and then pushed into the caps.

Long-standing partner

Harro Höfliger has been sup­porting T­hermo Fisher for more than three decades with the product assembly of the ImmunoCAP^TM test dis­penser. At the end of 2017, the fifth machine was deliv­ered to Upp­sala. In this system, the indi­vidual parts of the ImmunoCAP^TM test dis­penser are fed as bulk mate­rial to two cou­pled machines. Sep­a­rated in units of 15, the first machine pushes the caps into an inter­mit­tently rotating turret. Its first sta­tion serves to insert the sponges which are punched in par­allel from fleece soaked in liquid. A camera con­trols the pres­ence and posi­tion of the punched parts. Sub­se­quently, the pass-caps are moist­ened with buffer liquid. This is again fol­lowed by an optical dosage con­trol. Any fail-parts will be rejected. The caps are then con­veyed to the next inter­mit­tent machine, where the dis­penser tubes begin their journey.

Design and struc­ture of an ImmunoCAP^TM test dispenser

The ImmunoCAP^TM test dis­penser con­sists of five com­po­nents. A plastic tube, the epony­mous dis­penser, car­ries a cer­tain number of so-called caps in it. Each of these caps con­tains a sponge soaked in liquid. At the front, the dis­penser is closed with a remov­able plastic hat and at the back with a stopper. A weight between the stopper and the last cap ensures that the caps can easily slide for­ward and be removed auto­mat­i­cally by the lab­o­ra­tory system. 

Here, a camera checks the plastic tubes for damage before they are filled with caps. By recipe pre-selec­tion, the fill quan­tity of the dis­penser can be varied from ten to 16 caps. A slight vibra­tion of the tube after inser­tion ensures that the caps slide into each other easily. A mechan­ical fill level con­trol checks the tubes for cor­rect filling. A weight is placed on the last cap and its pres­ence is con­firmed mechan­i­cally. The stopper closes the ImmunoCAP™ test dis­penser at the back end. In the last assembly step, the hats, which are fed via a spiral con­veyor, are fitted. Grip­pers place all good dis­pensers into folding boxes in layers of ten.

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Photos: shutterstock.com/viewgene/cloik/Tim UR; istockphoto.com/Eraxion; stock.adobe.com/monebook, Helmar Lünig