The diagnosis of Rickettsiosis is difficult to make clinically for patients, because the symptoms are non-specific. IGeneX offers the following tests to help physicians in the accurate detection of Rickettsia.
The Rickettsia Immunofluorescent Assay (IFA) is designed to detect Rickettsia-specific antibodies in human serum. For diagnostic purposes, IFA test results should be used in conjunction with other data available to the diagnosing physician.
Principal
The Rickettsia IFA assay is a two-stage sandwich assay, based upon an antigen-antibody complex formation in the following steps:
Reference Range
Clinical Significance
The Rickettsia IFA is used to detect antibodies to Rickettsia species in human serum. These species include R. ricketsii and R. typhi, known to cause Rocky Mountain Spotted Fever and Murine Typhus, respectively. Titers rise during the first two-to-four weeks of illness and decline over the next six-to-12 months. In patients with previously high titers, titers of less than 160 may indicate a resolving infection. If the IFA result is negative but the clinical symptoms are present, polymerase chain reaction (PCR) testing is suggested.
The polymerase chain reaction (PCR)-based diagnostic assay for detection of Rickettsia from blood is highly specific to R. rickettsii and R. felis/typhi DNAs. The combination of the following three steps imparts a very high specificity and sensitivity to the test:
Reference Range
Clinical Significance
The Rickettsia species PCR test is an assay that detects Rickettsia species-specific DNA in clinical samples. Rickettsia 17 kDa antigen gene fragments are hybrid-selected by probes, followed by PCR amplification of the selected DNA fragment. PCR products are tested with Rickettsia-specific probes (R. rickettsii and R. felis/typhi) by southern blot assays. The primers and probes used for the selection of Rickettsia gene fragment encoding the 17 kDa antigen DNA fragments are designed from published sequences.
Limitations
| Panels | Blood | Urine | Misc |
| *CP1 | Co-infection Panel 1 | ✓ | ||
| CP4 | Co-infection Panel 4 | ✓ | ||
| CP5 | Co-infection Panel 5 | ✓ | ||
| RP1 | Rickettsia Panel 1 | ✓ | ||
| (*) Not yet available for New York residents. | |||
