Tests Information
| Serology | |||
|---|---|---|---|
| Test Name | Organism | Description & Interpretation | Sensitivity / Specificity |
| African trypanosomiasis CATT | Trypanosoma brucei gambiense |
Description: Human african trypanosomiasis, known as “sleeping sickness”, is caused by the parasite Trypanosoma brucei. It is acquired through the feces of an infected tsetse fly and passes into the bloodstream to reach other blood fluids. T.b.gambiense is found in large areas of West and Central Africa. T.b.rhodesiense causes East African sleeping sickness. The test procedure is an agglutination assay (CATT = Card Agglutination Test for Trypanosomiasis) that detects circulating antibodies against several surface antigens of T. b. gambiense by direct agglutination. Interpretation: 1) The CATT-antigen is a freeze-dried suspension of purified, fixed and stained bloodstream form trypanosomes expressing a predominant variable antigen type of T. b. gambiense. 2) Sensitivity: 87-98%; may take 2 to 8 weeks to develop detectable antibodies. 3) Specificity: 95%, cross-reactions with malaria and other parasitic diseases possible. |
Sensitivity: 87-98% Specificity: 95% |
| American trypanosomiasis ELISA & Immunoblot | Trypanosoma cruzi |
Description: Chagas disease is acquired through contact with feces of an infected triatomine bug. Infection can also occur congenitally, via transfusions, or organ transplants. Blood smears are limited to the acute phase. Serology is used for chronic phase. ELISA detects antibodies; Immunoblot available for confirmatory testing. Interpretation (ELISA): 1) Antigen: culture of T. cruzi epimastigotes. 2) Sensitivity (IgG-ELISA): 100% for indeterminate and chronic stages. 3) OD ≥ 0.4 indicates infection; may take 2–8 weeks to develop detectable antibody in acute cases. 4) Specificity: 96%; cross-reactions with leishmaniosis, malaria, syphilis. 5) Equivocal results require follow-up. Interpretation (Immunoblot): 1) Uses purified excreted-secreted antigens (TESA). 2) Sensitivity 100%, specificity 98%. Reactive bands at 220, 170, 120, 85, 60 kDa indicate positive. Positive 60 kDa may cross-react with Leishmania. Disclaimer: Laboratory-developed test, not approved by Health Canada. |
ELISA Sensitivity: 100% / Specificity: 96% Immunoblot Sensitivity: 100% / Specificity: 98% |
| Amebiasis ELISA | Entamoeba histolytica |
Description: Acquired by ingesting cysts in contaminated food, water, or soiled hands. Causes asymptomatic, gastrointestinal, or extra-intestinal infections. ELISA detects antibodies. Interpretation: 1) Uses NIH-200 strain antigens. 2) Sensitivity: 90–100% for extraintestinal, 70–80% for invasive intestinal. 3) Positive titers may persist years; interpret with caution. 4) Paired specimens may be used. |
Sensitivity: 92% Specificity: 100% |
| Babesiasis IFA | Babesia microti |
Description: Transmitted by ticks, can be co-transmitted with Anaplasma or Borrelia. IFA detects antibodies using infected erythrocytes. Interpretation: 1) Antigens from human strain. 2) Sensitivity 100% (except AIDS patients). 3) Specificity 99%; little cross-reactivity, some with Plasmodium. 4) Useful after parasitemia cleared. 5) Titers ≥1:64 indicate infection; titer patterns suggest timing. |
Sensitivity: 100% Specificity: 99% |
| Baylisascariasis Immunoblot | Baylisascaris |
Description: Infection from raccoon roundworm; can affect eyes, organs, brain. Immunoblot detects antibodies. Interpretation: 1) Recombinant RAG1 protein from L3 stage used. 2) Sensitivity: 88%, specificity: 98%. Higher sensitivity possible. No cross-reactivity with Toxocara. 3) Positive results supported by exposure evidence. |
Sensitivity: 88% Specificity: 98% |
| Cysticercosis Immunoblot | Taenia solium |
Description: Acquired by ingesting eggs or cysts. Neurocysticercosis can cause seizures, intracranial pressure, mental disorders. Immunoblot detects specific antibodies. Interpretation: 1) Uses lentil-lectin affinity-purified antigens from pigs. 2) Sensitivity: 98% in neurocysticercosis with ≥2 cysts, lower for single/subcutaneous cysts (28–72%, <50%). 3) Specificity: 100%. 4) Serum and CSF may be tested. |
Sensitivity: 98% Specificity: 100% |
Tests Information
| Serology (Extended) | |||
|---|---|---|---|
| Test Name | Organism | Description & Interpretation | Sensitivity / Specificity |
| Echinococcosis ELISA | Echinococcus species |
Description: Echinococcosis is infection caused by cestodes of the genus Echinococcus and acquired by ingesting eggs from infected animals. Hydatid cysts often develop in liver, lung, spleen, brain. Immunodiagnostic methods provide serologic evidence without disturbing cyst. ELISA detects antibodies. Interpretation: 1) Uses E. granulosis cyst soluble antigens. 2) High sensitivity, specificity relatively low (10-15% false positives due to cross-reactions). 3) Negative titers possible with small, intact, extrahepatic, or calcified cysts. 4) Interpret with caution if non-classic E. granulosus suspected. 5) Paired specimen testing may be useful. |
Sensitivity: 97.8% Specificity: 91.6% |
| Fascioliasis ELISA | Fasciola hepatica |
Description: Fascioliasis is caused by F. hepatica (“common liver fluke”), acquired from contaminated water plants. Serology detects F. hepatica-specific antibodies. Interpretation: 1) Uses recombinant protein antigen FhCatL5. 2) Sensitivity 100%, specificity 96%; cross-reactions possible with Trichinella or Toxocara. 3) Follow-up specimen required for equivocal results. |
Sensitivity: 100% Specificity: 96% |
| Filariasis ELISA | Brugia malayi |
Description: Lymphatic filariasis caused by thread-like worms; diagnosis via microfilariae in blood. Serology detects antibodies. Interpretation: 1) Uses antigens from adult worms. 2) Sensitivity 91%, specificity 84%; cross-reactions possible with Schistosoma, Strongyloides, Echinococcus. 3) OD ≥0.3 indicates infection at some unknown time. 4) Anti-filaria antibodies may persist for years. 5) Follow-up required if equivocal. |
Sensitivity: 91% Specificity: 84% |
| Filariasis ICT | Wuchereria bancrofti |
Description: Most filarial infections worldwide caused by W. bancrofti. Rapid ICT detects antigen in blood, serum, or plasma. Interpretation: In vitro immunochromatographic assay for qualitative detection of antigen. Recommended to confirm negative results by standard methods. Negative results do not preclude infection. |
Sensitivity: 99% Specificity: 93% |
| Gnathostomiasis ELISA | Gnathostoma spp |
Description: Infection by ingestion of undercooked freshwater fish. Causes skin swellings and eosinophilia. Interpretation: 1) Semi-quantitative ELISA using recombinant antigen. 2) Should be interpreted with clinical, epidemiological, and other lab findings. 3) Serology useful in endemic regions; false positives possible in non-endemic populations. |
Sensitivity: 93% Specificity: 100% |
| Leishmaniasis DAT | Leishmania donovani and L. infantum |
Description: Direct agglutination test (DAT) detects circulating antibodies for cutaneous and visceral leishmaniasis. DAT can detect antibodies before clinical symptoms. Interpretation: Infection results in production of circulating antibodies. DAT/VL antigen is freeze-dried suspension of trypsin-treated, fixed, stained promastigotes. Intended for screening and reference labs including antibody titration. |
Sensitivity: Not specified Specificity: Not specified |
| Malaria ELISA | Plasmodium falciparum, P. ovale, P. vivax, P. malariae, P. knowlesi |
Description: Detects antibodies to Plasmodium species; serology not for routine diagnosis of acute malaria. Interpretation: 1) Semiquantitative IgG determination using recombinant antigens. 2) Positive titers indicate past infection. 3) Useful for dormant infection, tropical splenomegaly, donor screening. 4) Cross-reactivity with Leishmania; double infections considered. |
Sensitivity: 99% Specificity: 96% |
Extended Serology & PCR Tests
| Serology Tests | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Test Name | Organism | Description & Interpretation | Sensitivity / Specificity | ||||||||||||||
| Paragonimiasis ELISA | Paragonimus westermani |
Description: Paragonimiasis is caused by Paragonimus flukes, commonly P. westermani. Infection occurs via ingestion of infected crab or crawfish. Diagnosis usually by egg detection in sputum; antibody tests aid differentiation from tuberculosis. Interpretation: 1) Semi-quantitative ELISA using Paragonimus antigen. 2) Interpret cautiously in non-endemic populations with clinical correlation. 3) Positive numbers depend on disease prevalence and selection criteria. |
Sensitivity: 100% Specificity: 85% |
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| Schistosomiasis ELISA | Schistosoma mansoni & S. haematobium |
Description: Infection by Schistosoma parasites; causes hepatosplenomegaly, liver or bladder disease. Diagnosis via egg detection or antibody ELISA. Interpretation: 1) Uses antigens from adult worms. 2) Sensitivity 96%, specificity 82%; cross-reactions possible. 3) OD ≥ 0.4 indicates infection at unknown time. 4) Follow-up for equivocal results. |
Sensitivity: 96% Specificity: 82% |
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| Strongyloidiasis ELISA & Immunoblot | Strongyloides stercoralis |
Description: Chronic infection causing eosinophilia, diarrhea. ELISA and confirmatory immunoblot detect specific antibodies. Interpretation ELISA: 1) Uses recombinant antigen NIE. 2) Sensitivity 100%, specificity 88%; cross-reactions possible. 3) Follow-up for equivocal results. 4) Antibodies decline over 6-12 months. Interpretation Immunoblot: 1) Sensitivity 100%, specificity 98%; confirmatory. 2) Antibodies decline over 6-12 months. |
ELISA: Sensitivity 100% / Specificity 88% Immunoblot: Sensitivity 100% / Specificity 98% |
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| Toxocariasis ELISA | Toxocara canis |
Description: Infection via ingestion of embryonated eggs from contaminated soil. Diagnosis by antibody detection. Interpretation: 1) Uses excretory-secretory antigen. 2) No gold standard; performance depends on species. 3) IgG proportional to larval burden. 4) Paired specimen testing may be useful. |
Sensitivity: 93.35% Specificity: 87.5% |
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| Toxoplasmosis ELFA | Toxoplasma gondii |
Description: Infection via cat feces, congenital, organ transplant, or undercooked meat. ELFA detects specific antibodies. Confirmatory test only. Interpretation: VIDAS TOXO IgM / IgG II / IgG Avidity (bioMérieux) used. |
Sensitivity / Specificity: Not specified | ||||||||||||||
| Trichinosis ELISA | Trichinella spiralis |
Description: Infection from undercooked meat. Detection of antibodies in serum confirms infection. Interpretation: 1) Uses excretory-secretory antigen from larvae. 2) IgG response proportional to larvae ingested. 3) Antibodies peak 3-6 months, decline progressively. 4) Paired specimen testing may be useful. |
Sensitivity: 85% Specificity: 93.8% |
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| PCR Tests | |||||||||||||||||
| Test Name | Organism | Description & Interpretation | Sensitivity / Specificity | ||||||||||||||
| African Trypanosomiasis PCR | Trypanosoma brucei |
Description: Human African sleeping sickness; diagnosis via PCR on blood or CSF. Interpretation: PCR amplifies 5’ junction of spliced leader sequence of T. brucei. Used for sensitive detection. |
Not specified | ||||||||||||||
| American Trypanosomiasis PCR | Trypanosoma cruzi |
Description: Chagas disease; PCR detects T. cruzi DNA in acute or reactivated chronic infection. Interpretation: Real-time PCR; sensitive and specific if Ct ≤ 33. Negative results do not fully exclude infection. |
Sensitivity: 90-100% Specificity: 100% |
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| Amebiasis PCR | Entamoeb
Other Tests
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