| Basic Characteristics | Properties (Haemophilus influenzae) |
| Capsule | Strain-dependent |
| Catalase | Positive (+ve) |
| Flagella | Negative (-ve) |
| Gas | Negative (-ve) |
| Gram Staining | Gram-negative |
| H2S | Negative (-ve) |
| Hemolysis | Negative (-ve) |
| Indole | Variable |
| Motility | Negative (-ve) |
| Nitrate Reduction | Positive (+ve) |
| Nitrite Reduction | Negative (-ve) |
| Oxidase | Positive (+ve) |
| Pigment | Absent or yellowish |
| Shape | Coccobacilli or small regular rods |
| Urease | Variable |
| V-factor requirement | Positive (+ve) |
| Adonitol | Negative (-ve) |
| Arabinose | Negative (-ve) |
| Cellobiose | Negative (-ve) |
| Dulcitol | Negative (-ve) |
| Erythritol | Negative (-ve) |
| Fructose | Negative (-ve) |
| Galactose | Positive (+ve) |
| Glucose | Positive (+ve) |
| Glycerol | Negative (-ve) |
| Inositol | Negative (-ve) |
| Inulin | Negative (-ve) |
| Lactose | Negative (-ve) |
| Maltose | Positive (+ve) |
| Mannitol | Negative (-ve) |
| Mannose | Negative (-ve) |
| Melibiose | Negative (-ve) |
| Raffinose | Negative (-ve) |
| Rhamnose | Negative (-ve) |
| Ribose | Positive (+ve) |
| Salicin | Negative (-ve) |
| Sorbitol | Negative (-ve) |
| Sorbose | Negative (-ve) |
| Sucrose | Negative (-ve) |
| Trehalose | Negative (-ve) |
| Xylose | Positive (+ve) |
| Alkaline Phosphatase | Positive (+ve) |
| Arginine Dihydrolase | Negative (-ve) |
| Esculin Hydrolysis | Negative (-ve) |
| Fucosidase | Negative (-ve) |
| IgA1 protease | Positive (+ve) |
| Lysine decarboxylase | Variable |
| Neuraminidase | Positive (+ve) |
| ONPG (β-galactosidase) | Negative (-ve) |
| Ornithine Decarboxylase | Variable |