Coro­na Rapid Tests are inten­ded to sup­ple­ment the limi­ted resour­ces avail­ab­le to con­tain the coro­na pan­de­mic with a fast, inex­pen­si­ve and decen­tra­li­zed scree­ning method. The­se are not desi­gned to replace the PCR test, but to com­ple­ment it.

The advice from cer­tain medi­cal cir­cles that an anti­bo­dy and/or rapid anti­gen test alo­ne is not suf­fi­ci­ent to rule out a suspec­ted case 100% is cor­rect. But this also app­lies to any other ana­ly­ti­cal method, inclu­ding the PCR test, which is of cour­se important as a detec­tion method. As the sole method, howe­ver, the PCR test quick­ly reaches its capa­ci­ty (labo­ra­to­ry equip­ment, can only be used cen­tral­ly) and eco­no­mic limits (cos­ts) world­wi­de, with which our health sys­tem is incre­a­singly con­fron­ted due to the deve­lo­p­ment of the rapidly incre­a­sing num­ber of infections.

The pro­te­ins of the immu­ne sys­tem that bind to the anit­gens of for­eign sub­s­tan­ces are cal­led immu­no­glo­bu­lins (Ig) or anti­bo­dies. They are manu­fac­tu­red to fight patho­gens such as bac­te­ria, viru­ses and para­si­tes. The main func­tion of Ig is to faci­li­ta­te the dest­ruc­tion of for­eign patho­gens. IgG and IgM are two clas­ses of immu­no­glo­bu­lins. The main dif­fe­rence bet­ween IgG and IgM is the IgG’s late reac­tion to a dise­a­se, while IgM is pro­du­ced immedia­te­ly after expo­sure to a par­ti­cu­la anti­gen. IgGs can be found throughout the body, main­ly in bodi­ly flu­ids, while IgMs are found in blood and lymph. IgGs pro­vi­de a long-term respon­se to a par­ti­cu­lar anti­gen and pro­vi­de las­ting immu­ni­ty. IgMs, howe­ver, show a short-term reaction.

The avail­ab­le resources/capacities for mole­cu­lar bio­lo­gi­cal mass tests, in our opi­ni­on, will not be suf­fi­ci­ent in the future. The­re are not enough labo­ra­to­ry dia­gnostic devices avail­ab­le, the swab mate­ri­als and access­ories can run out (see histo­ry of dis­in­fec­tants and respi­ra­to­ry masks) and qua­li­fied spe­cia­lists are often not avail­ab­le enough, e.g. sick them­sel­ves. Labo­ra­to­ries are cur­r­ent­ly often overloaded.

Coro­na Anti-gene and Anti-body One Step Rapid Tests can be car­ri­ed out inex­pen­si­ve­ly, decen­tral­ly and by any medi­cal spe­cia­list. The quick test sets are ful­ly equip­ped. No fur­ther labo­ra­to­ry equip­ment is requi­red. Results are avail­ab­le wit­hin 10–15 minu­tes after the test.

Sin­ce the­re is cur­r­ent­ly no spe­ci­fic the­ra­py or vac­ci­na­ti­on, anti-body and anti-gene rapid tests are pri­ma­ri­ly used as a scree­ning method, to ans­wer epi­de­mio­lo­gi­cal ques­ti­ons and for hygie­ne manage­ment, and not as a basis for the­ra­py decisi­ons. A pos­si­b­ly slight­ly lower spe­ci­fi­ci­ty com­pa­red to the PCR test can thus be easi­ly accep­ted here. In addi­ti­on, one can also reco­gni­ze asym­pto­ma­tic car­ri­ers, i.e. peop­le who can infect other peop­le, but are sym­ptom-free themselves.

It is also very important for our dai­ly work to know which pati­ent or employee is alrea­dy asym­pto­ma­tic. This is of gre­at con­cern with COVID-19, as asym­pto­ma­tic car­ri­ers play a huge role in the spread of the virus.

The ques­ti­on of an exis­ting immu­ni­ty after a pos­si­ble infec­tion is also of gre­at rele­van­ce, name­ly when it has to be deci­ded which employees (e.g. doc­tor, nur­sing staff) can cur­r­ent­ly look after infec­tious Covid-19 patients.

Anti­bo­dies can be detec­ted after about 7–10 days of infec­tion, which is why the Coro­na rapid test reli­es on the com­bi­na­ti­on of IgG and IgM detec­tion. The cour­se of anti­bo­dy for­ma­ti­on over time is clear­ly shown on this home­page and pro­vi­des you with actu­al infor­ma­ti­on that can sup­port you and your patients.

The ques­ti­on of detec­ta­bi­li­ty of anti­bo­dies over time is secon­da­ry in view of the incu­ba­ti­on time and pha­se of slow­ly incre­a­sing sym­ptoms las­ting around 7–10 days. It can be assu­med that a signi­fi­cant pro­por­ti­on of pati­ents will only pre­sent after a few days and will then alrea­dy have detec­ta­ble IgM.

A PCR test would usual­ly also take place only after the onset of symptoms.

If you have a posi­ti­ve test result, it is likely that you may have had COVID-19 and might have deve­lo­ped an anti­bo­dy respon­se to the virus. The­re is a small chan­ce that this test can give a posi­ti­ve result that is wrong (a fal­se posi­ti­ve result).

A nega­ti­ve test result means that the anti­bo­dies to the virus that cau­ses COVID-19 were not found in your sam­ple. Howe­ver, it is pos­si­ble for the test to give a nega­ti­ve result that is incor­rect (fal­se nega­ti­ve) in some peop­le with COVID-19. A nega­ti­ve result may occur if you are tes­ted ear­ly in your ill­ness and your body has­n’t had time to pro­du­ce anti­bo­dies to infec­tion. This means that you could pos­si­b­ly still have COVID-19 even though the test is negative.

The Covid-19 Anti­gen Test is an immu­no­chro­ma­to­gra­phic test and checks for pro­te­in com­pon­ents of the Sars-Cov‑2 pathogen.

It is a late­ral flow assay:

The test cas­set­te con­tains a con­ju­ga­te pad with col­lo­idal gold and a mem­bra­ne strip on the test line that is pre­coated with anti­bo­dies against the Sars-Cov‑2 antigen.

If Sars-Cov‑2 anti­gen is detec­ted in the sam­ple, a black line appears becau­se an anti­bo­dy-anti­gen-anti­bo­dy-gold con­ju­ga­te com­plex is formed.

The rapid anti­gen test pre­sen­ted on this page has a sen­si­ti­vi­ty of 92% and a spe­ci­fi­ci­ty of 98%. The anti­gen test shown on this home­page clo­ses the so-cal­led dia­gnostic gap to the anti­bo­dy rapid test.

The dia­gnostic gap, also known as the dia­gnostic win­dow, in medi­ci­ne, refers to the peri­od that elap­ses bet­ween infec­tion and the time from which the pre­vious or cur­rent pre­sence of a patho­gen in an orga­nism can be reli­ab­ly detec­ted by a spe­ci­fic test.

The rapid anti­gen test is car­ri­ed out with a nasal swab and checks for pro­te­in com­pon­ents of the Sars-Cov‑2 patho­gen; put sim­ply, the anti­gens bind the in the nasopha­rynx exis­ting virus and make it visi­ble and mea­sura­ble. It works just as quick­ly as an anti­bo­dy test: the test result is avail­ab­le wit­hin 15 minu­tes with reli­able accu­ra­cy (sen­si­ti­vi­ty: 92%, spe­ci­fi­ci­ty: 98%). This test pro­ce­du­re can the­re­fo­re also be used in the initi­al pha­se of a poten­ti­al ill­ness and in suspec­ted cases, even if no reco­gniz­ab­le sym­ptoms are displayed.

The sen­si­ti­vi­ty of a dia­gnostic test pro­ce­du­re indi­ca­tes the per­cen­ta­ge of sick pati­ents in which the respec­ti­ve dise­a­se is actual­ly reco­gni­zed by the app­li­ca­ti­on of the test, i.e. a posi­ti­ve test result occurs. It is defi­ned as the quo­ti­ent of true posi­ti­ve test results and the sum of true posi­ti­ve and fal­se nega­ti­ve test results.The hig­her the sen­si­ti­vi­ty of a test, the more reli­ab­ly it detects the dise­a­se. A nega­ti­ve result in a test with high sen­si­ti­vi­ty can rule out the dise­a­se you are loo­king for with a high degree of probability.

The spe­ci­fi­ci­ty of a dia­gnostic test pro­ce­du­re indi­ca­tes the pro­ba­bi­li­ty that actual­ly healt­hy peop­le who do not suf­fer from the dise­a­se in ques­ti­on will also be reco­gni­zed as healt­hy in the test. It is defi­ned as the quo­ti­ent of true nega­ti­ve test results and the sum of fal­se posi­ti­ve and true nega­ti­ve test results — i.e. all test results that were actual­ly not based on any disease.The cal­cu­la­ti­on is based on (SPE = specificity):

  • SPE = cor­rect­ly reco­gni­zed as healt­hy / all healthy

Anti­gens are for­eign pro­te­ins against which the immu­ne sys­tem forms anti­bo­dies. It is not a gene in the tra­di­tio­nal sen­se. The word ‘anti­gen’ is not deri­ved from ‘gene­tics’, but from the English -

‘anti­bo­dy genera­ting’ (= pro­du­cing antibodies).