Prevalence of acute bartonellosis in study group: 51% (based on positive blood cultures)
Criteria for acute bartonellosis - all of the following:
(1) fever
(2) arthralgia
(3) one or more of the following:
(3a) hemoglobin < 12 g/dL or hematocrit < 36%
(3b) reticulocyte index > 2%
(3c) hepatomegaly
where:
• The temperature used to define fever was not specified. A value > 100.5°F (> 38°C) might be used.
• There are several equations for converting hemoglobin and hematocrit (see Section 03.06.02). A simple formula is hemoglobin = (hematocrit in percent) / 2.941
• The reticulocyte index was not defined. Because the test needs to be done cheaply in a developing country, my guess this refers to the simple reticulocyte count. Alternatively this could refer to the reticulocyte production index, which corrects for concurrent anemia.
Performance:
• Sensitivity 70.2% (95% CI 59-74%) and specificity 64.4% (95% CI 54-74%)
• Positive and negative predictive values were 67%.
Limitations:
• The definition would work better in an area of high prevalence than in one that has a low prevalence.
NOTE: A previous case definition using fever, pallor and jaundice was fairly specific (94.5%) but insensitive (18.2%).
