Rickettsia – Serology

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Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Rickettsia serology, or Murine typhus, or M typhus, or Rocky Mountain spotted fever, or RMSF	General Test Requisition	Serum	5.0 ml whole blood or 1.0 ml serum	Vacutainer tubes (SST)

Submission and Collection Notes

Provide clinical symptoms, exposure, and onset date on the General Test Requisition Form if diagnosis is required.

Timing of Specimen Collection

An acute (collected early after the onset of symptoms) and a convalescent (collected 2-3 weeks later) may be required for laboratory diagnosis.

Limitations

Haemolysed, icteric, lipemic or microbially contaminated sera or plasma are not recommended for testing.

Storage and Transport

Centrifuge if using SST. Label specimens with at least two identifiers; place it in biohazard bag and seal. Specimens should be stored at 2-8°C following collection and shipped to PHL on ice packs.

Special Instructions

An acute (collected early after the onset of symptoms) and a convalescent (collected 2-4 weeks later) is highly recommended for laboratory based diagnosis of rickettsial infection.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Rickettsia serology testing is performed once per week.

Turnaround time is up to 10 days.

Test Methods

Rickettsia IgG serology assays are performed using Indirect Immunofluorescence Assay (IFA) for Rocky Mountain Spotted Fever and Murine typhus.

Antibody reactivity to the R.rickettsii antigen should be considered positive for the Rocky Mountain Spotted Fever group, whereas antibody reactivity to the R.typhi antigen should be considered positive for Typhus Fever group.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

References

LAB-SD-138 Rickettsia Serology - Test algorithm for Rocky Mountain spotted fever group and Murine typhus