Laboratory Diagnosis of Tick-Borne Infections

Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis

July 2010

So let’s review the conventional laboratory methods that are used for the diagnosis of ehrlichiosis and anaplasmosis. The first method I’d like to discuss is direct examination of peripheral blood smears. This technique has been used for many years in clinical laboratories, and remains one of the most rapid diagnostic methods in cases of suspected ehrlichiosis. In this test, laboratory technologists examine the peripheral smear for the presence of monocytes or granulocytes containing morulae, which is a latin term for “mulberry.”

As you can see in the images on the right-hand side of this slide, the organisms can be seen in characteristic clusters resembling mulberries. While the identification of morulae in peripheral blood smears is relatively specific, it is very insensitive for human monocytic ehrlichiosis, or HME, which is caused by Ehrlichia chaffeensis. We do see a slightly increased sensitivity in cases of human granulocytic anaplasmosis, or HGA, which is caused by Anaplasma phagocytophilum. However, it is still a relatively rare observation, with only 25 to 75% of smears being positive. I should also mention that empiric antimicrobial treatment may further decrease the sensitivity of smear, so ideally, a blood sample should be obtained prior to the initiation of therapy.

< Previous Slide

Conventional Methods for Diagnosis

Next Slide >

 

Jump to section:

• Introduction
• Outline
• Patient Case 1
• Laboratory Workup
• Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis
• Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis
• Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis
• Typical Positive Result by IFA
• Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis
• Diagnostic Tests for HME and HGA
• Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis
• Conventional Methods for Diagnosis of Ehrlichiosis and Anaplasmosis
• Patient Case 2
• Giemsa-stained Preparation Slide
• Giemsa-stained Preparation Slide
• Conventional Methods for Diagnosis of Babesia
• Conventional Methods for Diagnosis of Babesia
• Conventional Methods for Diagnosis of Babesia
• Conventional Methods for Diagnosis of Babesia
• Conventional Methods for Diagnosis of Babesia
• Patient Case 3
• Lyme Disease - Diagnostic Approach
• Conventional Methods for Diagnosis of Lyme Disease
• Patient Case 3 (continued)
• Diagnosis of Lyme Disease
• Lyme Disease - Serologic Assays
• Lyme Disease - Serologic Assays
• Lyme Disease - Serologic Assays
• Patient Case 3 (continued)
• Lyme Disease - Serologic Assays
• Patient Case 3 (continued)
• Lyme Disease - Factors to Consider
• Conclusions
• References
• Questions?