Table 5 Overall efficacy of 10% KOH wet‐mount preparation and Gram‐stained smear in the detection of fungus, bacteria (including Nocardia) and Acanthamoeba from corneal scrapes obtained from eyes (n = 3298) with infective keratitis.
| Sl no | Direct microscopic investigations | Results | No of eyes | Culture | Sensitivity (%) | Specificity (%) | Positive predictive value (%) | Negative predictive value (%) | |
|---|---|---|---|---|---|---|---|---|---|
| Positive | Negative | ||||||||
| 1 | Detection of fungus, Nocardia and Acanthamoeba in 10% KOH wet‐mount preparation | Positive | 1308* | 1289† | 19 | 99.1 | 99.0 | 98.5 | 99.4 |
| Negative | 1990‡ | 12§ | 1978 | (95% CI 98.3 to 99.5) | (95% CI 98.5 to 99.4) | (95% CI 97.7 to 99.1) | (95% CI 98.9 to 99.7) | ||
| Total | 3298 | 1301¶ | 1997 | ||||||
| 2 | Detection of bacteria (including Nocardia), fungi and Acanthamoeba in Gram‐stained smear | Positive | 2352** | 2300†† | 52 | 93.8 | 93.9 | 97.8 | 83.9 |
| Negative | 946‡‡ | 152§§ | 794 | (95% CI 92.8 to 94.7) | (95% CI 92.0 to 95.3) | (95% CI 97.1 to 98.3) | (95% CI 81.4 to 86.2) | ||
| Total | 3298 | 2452*** | 846 | ||||||
*Of 1308 eyes, 1230 were found to be positive for fungus, 46 were positive for Nocardia and 32 were positive for Acanthamoeba in 10% KOH wet‐mount preparation.
†Of 1289 eyes, 1211 had fungal growth, 46 had Nocardia growth and 32 had Acanthamoeba growth.
‡Eyes negative for fungus, Nocardia and Acanthamoeba in KOH wet‐mount preparation.
§Of 12 eyes, 9 had fungal growth and 3 had Acanthamoeba growth.
¶Of 1301 eyes, 1220 had fungal growth, 46 had Nocardia growth and 35 had Acanthamoeba growth.
**Of 2352 eyes, 1088 were found to be positive for fungus, 1203 were positive for bacteria, 40 were positive for Nocardia and 21 were positive for Acanthamoeba in Gram‐stained smear.
††Of 2300 eyes, 1088 eyes had fungal growth, 1151 eyes had bacterial growth, 40 had Nocardia growth and 21 had Acanthamoeba growth.
‡‡Eyes negative for fungus, bacteria (including Nocardia) and Acanthamoeba in Gram‐stained smear.
§§Of 152 eyes, 132 eyes had fungal growth, 6 had Nocardia growth and 14 had Acanthamoeba growth.
***Of 2452 eyes, 1220 had fungal growth, 1151 had bacterial growth, 46 had Nocardia growth, 35 had Acanthamoeba growth.