Trichomonas vaginalis antigens in vaginal and urine specimens by immunochromatography, compared to culture and microscopy

This study evaluated the immunochromatographic [1C] capillary flow technology for detection of T. vaginalis antigens in vaginal and urine specimens. The 1C antigen-detection test and microscopy wet smears were assessed against the InPouch TV culture. Vaginal-swabs and first-voided urine specimens were obtained from 348 sexually active symptomatic or asymptomatic, >/= 16 years old women. Nineteen samples [5%] were positive by culture [95%, CI 0.3-0.8]. The 1C test [vaginal-specimens] was more sensitive than the wet smears. 1C sensitivity was 84% [95%CI, 0.68-1.01], specificity 98% [95%CI, 0.96-0.99], positive predictive value [PPV] 70% [95%CI, 0.51-0.88], negative predictive value [NPV] 99% [95%CI, 0.98-1], [positive likelihood ratio [+LR]: 39.6, and negative likelihood ratio [-LR] 0.2. The 1C test using urine as a substrate had less performance than both microscopy and 1C .test of vaginal specimens. Urine-IC sensitivity was 53% [95%CI, 0.30-0.75], specificity 99% [95% CI, 0.98-1.00], PPV 77% [95%CI, 0.54-1], NPV 97% [95%CI, 0.96-0.99], +LR: 57.7, and -LR: 0.5. Sensitivity of vaginal smear was 68% [95%CI, 0.48-0.89], specificity 100%, PPV 100% [95% CI, 1], NPV 98% [95% CI, 0.97-1], +LR>225, and -LR: 0.3. T. vaginalis was diagnosed in two wet urine samples, but not in smears. The 1C antigen improved T. vaginalis diagnosis, especially in screening, rapid, or point-of-care test, but in urine was less reliable than with vaginal smear

Antigen capture immuno-chromatographic strip format in detecting parasite-specific lactate dehydrogenase to diagnose malaria in non-immune patients

Several rapid diagnostic test devices [RDT] based on detection of malaria antigen in the whole blood were developed. OptiMal test the presence of parasite-specific lactate dehydrogenase [LDH] enzyme using three monoclonal antibodies was used. Two monoclonal antibodies were pan-specific and recognized all malaria species. The third one was specific only for Plasmodium falciparum. The parasite antigens were detected using an antigen-capture immunochromatographic strip format. One hundred-nine malaria positive and 730 malaria negative cases diagnosed by microscopy were included. 75/109 were P. flaciparum 26 as P. vivax, 3 P. malariae and 5 mixed infection of P. falciparum and P. vivax. The RDT showed a low sensitivity [85%, 95% Confidence Interval [CI], 79-92%] with a much lower sensitivity in detecting species other than P. falciparum as well as in mixed infections. The sensitivity was 50% for less than 200 parasites/micro. The sensitivity of OptiMal for P. falciparum was 87% [95% CI,79-94], 81% [95% CI,66-96] for P. vivax, and failed with P. malariae. Mixed infections were misdiagnosed as P. falciparum. The sensitivity of OptiMal was quite good in detecting both P. falciparum and P. vivax [98%; 95%C1, 97-99 and 100%; 95%CI, 100-100 respectively] and 99% [95%CT, 98-99] for all species. The positive and negative ratio for all malaria species was: [+LR= 62.3, -LR= 0.01]; for P. falciparum [+LR =3 8.9, -LR=0.01] and for P. vivax [+LR=0.8077/0,-LR=0.2]. The test value to assess drug resistance in post treatment days was discussed