Sensitivity and specificity of CRP and symptom screening as tuberculosis screening tools among HIV-positive and negative outpatients at a primary healthcare facility in Lusaka, Zambia: a prospective cross-sectional study

Abstract

ObjectivesTo evaluate the performance of point-of-care C-reactive protein (CRP) as a screening tool for tuberculosis (TB) using a threshold of 10 mg/L in both people living with HIV (PLHIV) and HIV-negative individuals and compare it to symptom screening using a composite reference for bacteriological confirmation of TB.MethodsProspective cross-sectional study.SettingA primary healthcare facility in Lusaka, Zambia.ParticipantsConsecutive adults (≥18 years) presenting for routine outpatient healthcare were enrolled. Of the 816 individuals approached to participate in the study, 804 eligible consenting adults were enrolled into the study, of which 783 were included in the analysis.Primary outcome measuresSensitivity, specificity, positive predictive value and negative predictive value (NPV) of CRP and symptom screening.ResultsOverall, sensitivity of WHO-recommended four-symptom screen (W4SS) and CRP were 87.2% (80.0–92.5) and 86.6% (79.6–91.8) while specificity was 30.3% (26.7–34.1) and 34.8% (31.2–38.6), respectively. Among PLHIV, sensitivity of W4SS and CRP was 92.2% (81.1–97.8) and 94.8% (85.6–98.9) while specificity was 37.0% (31.3–43.0) and 27.5% (22.4–33.1), respectively. Among those with CD4≥350, the NPV for CRP was 100% (92.9–100). In the HIV negative, sensitivity of W4SS and CRP was 83.8% (73.4–91.3) and 80.3% (69.5–88.5) while specificity was 25.4% (20.9–30.2) and 40.5% (35.3–45.6), respectively. Parallel use of CRP and W4SS yielded a sensitivity and NPV of 100% (93.8–100) and 100% (91.6–100) among PLHIV and 93.3% (85.1–97.8) and 90.0% (78.2–96.7) among the HIV negatives, respectively.ConclusionSensitivity and specificity of CRP were similar to symptom screening in HIV-positive outpatients. Independent use of CRP offered limited additional benefit in the HIV negative. CRP can independently accurately rule out TB in PLHIV with CD4≥350. Parallel use of CRP and W4SS improves sensitivity irrespective of HIV status and can accurately rule out TB in PLHIV, irrespective of CD4 count.

Clinic presentation delay and tuberculosis treatment outcomes in the Lake Victoria region of East Africa: A multi-site prospective cohort study

“…Increasing or introducing TB screening into these non-clinical settings may be effective in reducing clinic presentation delays. Still, the often low positive predictive value of symptom-based TB screening [37][38][39][40] warrants consideration. Especially in highly resource-limited settings, the costs and potential benefits of expanded TB screening should be weighed against those of other efforts to improve individual and public health [41].…”

Comparative Study on the Efficacy of Two Perioperative Chemotherapy Regimens for Lumbar Brucellosis

“…According to most studies, preoperative ESR does not correlate significantly with prognosis due to the fact that in many cases, it is not consistent with clinical manifestations and is easily affected by a variety of disease states, while CRP is highly sensitive and specific. 27,28 It has been proven that a rapid decrease in CRP after spinal tuberculosis correlates with an improvement in neurological function, in addition to surgical removal of casein-like materials from the spinal canal, the use of chemotherapeutic agents is also effective in reducing spinal cord and nerve root inflammation. 3 In clinical settings, therefore, it is advantageous to find a combination of drugs that reduces perioperative infection index (ESR, CRP) faster and does not have any obvious adverse effects.…”