Rickettsia rickettsii Antibody, IgG & IgM

Label Mnemonic:	RMSGM
Epic code:	LAB7511
Downtime form:	A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Commercial Mailout Laboratory
6240-8 RCP
356-8593

Specimen(s):

Serum

Specimen Instructions:

Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimen plainly as "acute" or "convalescent."

Collection Medium:

Red top tube 5 mL (Clot Activator)

Minimum:

Preferred Minimum: 1 mL serum in a red top tube
Absolute Minimum: 0.3 mL serum in a red top tube

Rejection Criteria:

Contaminated, hemolyzed, or severely lipemic specimens.

Testing Schedule:

Test performed: Sunday - Saturday

Turn Around Time:

1-3 days upon receipt at reference laboratory

Reference Range:

Rickettsia rickettsii Antibody, IgG
  Less than 1:64: Negative - No significant level of Rickettsia
  rickettsii Antibody, IgG detected.
  1:64 - 1:128: Low Positive - Presence of Rickettsia rickettsii
  Antibody, IgG detected, suggestive of current or past infection.
  1:256 or greater: Positive - Presence of Rickettsia rickettsii
  Antibody, IgG suggestive of recent or current infection.

Rickettsia rickettsii Antibody, IgM
  Less than 1:64: Negative - No significant level of Rickettsia
  rickettsii Antibody, IgM detected.
  1:64 or greater: Positive - Presence of Rickettsia rickettsii
  Antibody, IgM detected, which may indicate a current
  or recent infection; however, low levels of IgM antibodies may
  occasionally persist for more than 12 months post-infection.

Interpretive Data:

The best evidence for current infection is a significant change on two appropriately timed specimens, where both tests are done in the same laboratory at the same time.

The CDC does not use IgM results for routine diagnostic testing of Rocky Mountain Spotted Fever, as the response may not be specific for the agent (resulting in false positives) and the IgM response may be persistent from past infection.

Methodology:

Semi-Quantitative Indirect Fluorescent Antibody

CPT Code:

86757 x2