Sorted By Test Name - Mayo Medical Laboratories

FELAS
90158
presented with fever, myalgias and leukopenia. Diagnosis of ehrlichiosis may be difficult since the
patient's clinical course is often mild and nonspecific. This symptom complex is easily confused with
other illnesses such as influenza, or other tick-borne zoonoses such as Lyme disease, babesiosis, and
Rocky Mountain spotted fever. Clues to the diagnosis of ehrlichiosis in an acutely febrile patient after tick
exposure include laboratory findings of leukopenia or thrombocytopenia and elevated serum
aminotransferase levels. However, while these abnormal laboratory findings are frequently seen, they are
not specific. Rarely, intragranulocytic or monocytic morulae may be observed on peripheral blood smear,
but this is not a reliable means of diagnosing cases of human ehrlichiosis/anaplasmosis. Definitive
diagnosis is usually accomplished through PCR and/or serology methods. PCR techniques allow direct
detection of pathogen-specific DNA from patients' whole blood during the acute phase of disease. This is
currently the test of choice for the newly described EML organism. Serologic testing is usually done only
for confirmatory purposes, by demonstrating a 4-fold rise or fall in specific antibody titers to Ehrlichia
species or Anaplasma antigens. There is not currently a specific serologic test for the EML organism, and
cross-reactivity with the other Ehrlichia species by serology may be unreliable. It is important to note that
concurrent infection with Anaplasma phagocytophilum, Borrelia burgdorferi, and Babesia microti is not
uncommon as these organisms share the same Ixodes tick vector, and additional testing for these
pathogens may be indicated.
Useful For: Evaluating patients suspected of human granulocytic anaplasmosis or human monocytic
ehrlichiosis
Interpretation: Positive results indicate presence of specific DNA from Ehrlichia chaffeensis,
Ehrlichia ewingii, Ehrlichia muris-like, or Anaplasma phagocytophilum and support the diagnosis of
ehrlichiosis or anaplasmosis. Negative results indicate absence of detectable DNA from any of these 4
pathogens in specimens, but it does not exclude the presence of the organism or active/recent disease.
Since DNA of Ehrlichia ewingii is indistinguishable from that of Ehrlichia canis by this rapid PCR assay,
a positive result for Ehrlichia ewingii/Ehrlichia canis indicates the presence of DNA from either of these 2
organisms.
Reference Values:
Negative
Clinical References: 1. Bakken JS, Dunler JS: Human granulocytic ehrlichiosis. Clin Infect Dis
2000 Aug;31(2):554-560 2. Dunler JS, Bakken JS: Human ehrlichioses: newly recognized infections
transmitted by ticks. Ann Rev Med 1998;49:201-213 3. Krause PJ, McKay K, Thompson CA, et al:
Disease-specific diagnosis of coinfecting tickborne zoonoses: babesiosis, human granulocytic ehrlichiosis,
and Lyme disease. Clin Infect Dis 1999 May 1;34(9):1184-1191 4. McQuiston JH, Paddock CD, Holman
RC, Childs JE: The human ehrlichioses in the United States. Emerging Infect Dis 1999
Sept-Oct;5(5):635-642
Elastase, Pancreatic, Serum
Clinical Information: Serum Elastase, also called Pancreatopeptidase, is a protease present in
pancreatic secretion with the unique ability to rapidly hydrolyze elastin. Elastin is a fibrillar protein found
in connective tissue. Elastin forms the elastic fibers found mostly in lungs and skin. Elastase is able to
hydrolyze denatured hemoglobin, casein, fibrin, albumin and denatured but not native collagen. Elastase
has been implicated in the pathogenesis of pulmonary emphysema, atherosclerosis and in the vascular
injury of acute pancreatic necrosis. Elastase activity is inhibited by protease inhibitors including
a1-Anti-Trypsin, a1-anti-Chymotrypsin, anti-Thrombin III, a2-Macroglobulin and b1-anti-Collagenase.
Patients with thyroid dysfunction have decreased Elastase activity. Serum pancreatic levels quantify EL 1
for the diagnosis or exclusion of an acute pancreatitis or an inflammatory episode of chronic pancreatitis
or gallstone induced pancreatitis.
Reference Values:
Adult Reference Ranges:
Normal pancreatic exocrine function:
Less than 3.5 ng/mL
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