Ordering Recommendation

Detects antibodies during convalescent phase.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation
Collect

Serum Separator Tube (SST).

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP standard transport tube. (Min: 0.4 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens.

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Contaminated, hemolyzed, or severely lipemic specimens.

Remarks

Mark specimens plainly as "acute" or "convalescent."

Stability

After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Methodology

Semi-Quantitative Indirect Fluorescent Antibody (IFA)

Performed

Sun-Sat

Reported

1-3 days

Reference Interval

Test Number
Components
Reference Interval
  Rocky Mt Spotted Fever IgG Less than 1:64

Interpretive Data

Antibody reactivity to Rickettsia rickettsii antigen should be considered Spotted Fever group reactive. Other organisms within the group include R. akari, R. conorrii, R. australis, and R. sibirica.

Seroconversion, a fourfold or greater rise in antibody titer, between acute and convalescent sera is considered strong evidence of recent infection. Acute-phase specimens are collected during the first week of illness and convalescent-phase samples are generally obtained 2-4 weeks after resolution of illness. Ideally these samples should be tested simultaneously at the same facility. If the sample submitted was collected during the acute-phase of illness, submit a marked convalescent sample within 25 days for paired testing.


Component
Unit Of Measure
Interpretation
Rocky Mt Spotted Fever, IgG Less than 1:64
1:64 - 1:128
1:256 or greater
Negative - No significant level of IgG antibody detected.
Low Positive - Presence of IgG antibody detected, suggestive of current or past infection.
Positive - Presence of IgG antibody suggestive of recent or current infection.

Compliance Category

FDA

Note

Hotline History

N/A

CPT Codes

86757

Components

Component Test Code* Component Chart Name LOINC
0050369 Rocky Mt Spotted Fever IgG 5307-4
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • Rickettsia
  • RMSF
  • Rocky Mountain Spotted Fever
Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibody, IgG