Evaluating Cryptococcal Antigen Lateral Flow Assay by Fingerstick Whole Blood in HIV-Infected Persons with Meningitis
Methods: From August 2013 until April 2014, CRAG LFA tests (IMMY, Norman, Oklahoma) were performed on fingerstick whole blood, plasma and/or serum in 179 HIV-infected adults who were admitted to Mulago National Referral hospital in Kampala, Uganda with symptoms of meningitis. A fingerstick CRAG LFA was performed (n=179). Venous blood was also collected and centrifuged to obtain serum and plasma (n=173). CSF was tested after lumbar puncture (n=189).
Results: Of the 173 meningitis patients with all specimen types tested, 127 (73%) were CRAG positive and 46 (27%) were CRAG negative. In 100% of 173 tests performed, there was agreement between fingerstick whole blood, serum, and plasma in both positive and negative results (Kappa=1.0, 95%CI lower margin: 0.979). Of the 129 patients who tested CRAG+ by fingerstick, 119 (92%) had cryptococcal meningitis with a positive CSF CRAG. Ten (5.6%) had isolated cryptococcal antigenemia with a negative CSF CRAG. No persons with cryptococcal meningitis had a negative fingerstick.
Conclusion: The 100% agreement between whole blood, serum, and plasma CRAG LFA results demonstrate that fingerstick is a viable option for detecting CRAG, particularly in settings where phlebotomy is not available. Additionally, using fingerstick CRAG LFA allows healthcare centers to rapidly screen a large number of patients, and prioritize among whom to measure CSF opening pressure or empirically remove a large volume of CSF.
S. Velamakkani, None
R. Kiggundu, None
D. Meya, None
J. Rhein, None
D. Boulware, None