SeroCP Semi-quantitative IgA ELISA Assay


The SeroCP Semi-quantitative IgA ELISA Assay is an Enzyme Linked Immunosorbent Assay (ELISA) for the semi-quantitative determination of species-specific IgG antibodies to Chlamydia pneumoniae in human serum. The Eagle Biosciences SeroCP Quant IgG ELISA Assay Kit is for Research Use Only and is not intended for diagnostic or therapeutic purposes.

SKU: 293-01 Categories: , ,

SeroCP Semi-quantitative IgA ELISA Assay

The SeroCP Semi-quantitative IgA ELISA Assay is For Research Use Only

Size: 1×96 wells
Sensitivity: Cut-Off Control
Incubation Time: 2.25 hours
Sample Type: Serum
Sample Size: 10 µl
Alternative Name: Chlamydia pneumoniae, quant c. pneumoniae

Sensitivity and Specificity

The Eagle Biosciences SeroCP Quant IgA was evaluated against the SeroCP IgA (Catalog No. 193-01). The study used 230 sera samples from symptomatic individuals and 58 sera samples from healthy individuals.

Sensitivity and specificity were calculated:

Sensitivity: 218/230 = 94.8%
Specificity: 54/58 = 93.1%

Assay Principle

The Eagle Biosciences SeroCP Quant Plates are supplied coated with purified elementary bodies of C.pneumoniae (TWAR 183) as antigens. The serum to be tested is diluted and incubated in the SeroCP Quant plate for 1h at 37°C. In this step C.pneumoniae antibodies are bound to the immobilized antigens. Non-specific antibodies are removed by washing. Anti-human IgA conjugated to Horseradish Peroxidase (HRP) is added and incubated 1h at 37°C. In this step the HRP-Conjugate is bound to the prebound antigen-antibody complex. Unbound conjugate is removed by washing. Upon the addition of TMB-Substrate, the Substrate is hydrolyzed by the peroxidase, yielding a blue solution of the reduced chromogen. Upon the addition of the Stop Solution, the blue color turns yellow and should be read by an ELISA reader at a wavelength of 450/620nm.  The absorbance is proportional to the amount of the specific antibodies that are bound to the coated antigens.

Related Products

SeroCP Semi-quantitative IgG ELISA Assay
SeroCP RT C. pneumoniae IgA ELISA Assay
SeroCP C. pneumoniae IgA ELISA Assay

Additional Information

Assay Background

Chlamydia pneumoniae (TWAR-183) is an emerging infectious agent with a spectrum of clinical manifestations, including upper and lower respiratory tract infections. The majority of C.pneumoniae infections are mild and asymptomatic yet, may cause serious diseases, such as pharyngtitis, sinusitis, acute bronchitis and community acquired pneumonia. Undetected and untreated infection may lead to prolonged and persistent disease. Recent data indicates a possible association between C.pneumoniae infection and chronic diseases. Seroprevalence of C.pneumoniae among children is low but increases sharply until middle age, where after it remains high

Difficulties in sample collection and inaccessibility of the infected site seriously affect the usefulness of direct detection methods. Therefore, serological testing is routinely used and serves as a non-invasive tool in identification of both distal and chronic chlamydial infections, where direct detection methods are rarely efficient. In addition, the presence of certain antibody types may also indicate the state of the disease. Primary chlamydial infection is characterized by a predominant IgM response within 2 to 4 weeks and a delayed IgG and IgA response within 6 to 8 weeks. After acute C.pneumoniae infection, IgM antibodies are usually lost within 2 to 6 months, IgG antibody titers usually decrease slowly; whereas IgA antibodies tend to disappear rapidly. When primary chlamydia infection is suspected, the detection of IgM is highly diagnostic. However, in recurrent or chronic infections the prevalence of IgM is low and therefore absence of IgM does not necessarily exclude on-going infection. In reinfection, IgG and IgA levels rise quickly, often in one to two weeks.

IgA antibodies have shown to be a reliable immunological marker of primary, chronic and recurrent infections. These antibodies usually decline rapidly to baseline levels following treatment and eradication of the chlamydia infections. The persistence of elevated IgA antibody titers is generally considered as a sign of chronic infection. IgG antibodies persist for long periods and decline very slowly. Therefore, the presence of IgG antibodies is mainly indicative of a chlamydia infection at an undetermined time. However, a four-fold rise in IgG or high levels of IgG antibodies may indicate an on-going chronic infection.

SeroCP Quant is an ELISA based assay in which purified elementary bodies of C.pneumonaie (TWAR-183) are used as antigens to detect the antibody response in humans. For complete diagnosis of current, chronic or past infections, it is recommended to determine IgG, IgM and IgA antibodies to C.pneumoniae.


Kuo, C.C., Jackson L.A. and Grayston, J.T. (1995). Chlamydia pneumoniae (TWAR) Clin Microbiol REV; 8:451-461.

Saikku, P., Leinonen, M., Tenkanen, L., Linnanmaki, E., Ekman, M.R., Manninen, V.,Manttari, M., Frick, M.H. and Huttunen, J.K. (1992). Chronic Chlamydia pneumoniae infection as a risk factor for coronary heart disease in the Helsinki heart study. Ann. Intern. Med. 116: 273-278.

Puolakkainen, M., Saikku, P., Leinonen, M., Nurminen, M., Vaananen, P. and Makela, P.H. (1984). Chlamydia pnemonitis and its serodiagnosis in infants. J. Infect. Dis. 149: 598-604.

Campbell, L.A. (1993). PCR detection of Chlamydia pneumoniae In Diagnostic Molecular Microbiology: Principles and Applications (Persing, D.H., Smith, T.F., Tenover, F.C. and White, T.J., Eds). ASM Press. pp. 247-252.

Henry-Suchet, J., Askienazy-Elbhar, M., Thibon, M., Revol, C. and Akue, B.A. (1994)  Post-therapeutic evolution of serum chlamydia antibody titers in women with acute salpingitis and tubal infertility. Fertility and Sterility. 62: No. 3.

Saikku, P., Matila, K., Nieminen, M.S., Huttunen, J.K., Leinon, M., Eckman, M.R., Makela, P.H. and Valtonen, V. (1988). Serological Evidence of an Association of Novel Chlamydia TWAR with Chronic Coronary Heart Disease and Acute Myocardial Infarction. Lancet. 2: 983-986

Grayston, J.T., Cambell, L.A., Mordhorst, C.H., Saikku, P., Thom, D. and Wang, S.P. (1989). A New Respiratory Pathogen: Chlamydia pneumoniae Strain TWAR. J. Inf. Dis. 161: 618-625.

Saikku, P., Leinonen, M., Tenkanen, L., Linnanmaki, E., Ekman, M.R., Mannin, V. Manttari, M., Frick, M.H. and Huttunen, J.K. (1992). Chronic Chlamydia pneumoniae Infections as a Risk Factor for Coronary Heart Disease in the Helsinki Heart Study. Ann. of Int. Med. 116: 273-278.

Package Inserts

Please note: All documents above are for reference use only and should not be used in place of the documents included with this physical product. If digital copies are needed, please contact us.

Product Citations