## Diagnostic Approach to Trachoma **Key Point:** Giemsa staining of conjunctival scrapings is the gold standard for confirming active trachoma in resource-limited settings and remains the investigation of choice in India. ### Why Giemsa Staining? **High-Yield:** Giemsa stain reveals **intracytoplasmic inclusion bodies** (Halberstaedter-Prowazek inclusions) within epithelial cells of the conjunctiva. These are pathognomonic for *Chlamydia trachomatis* infection. ### Technique and Findings 1. Conjunctival scrapings obtained from upper tarsal conjunctiva 2. Smears prepared and stained with Giemsa stain 3. Inclusions appear as **dark purple/blue bodies** within the cytoplasm of epithelial cells 4. Sensitivity: 50–60% in active infection; higher in children ### Clinical Context **Clinical Pearl:** In this patient with: - Chronic follicular conjunctivitis - Corneal pannus (vascular infiltration of superior cornea) - Rural endemic area (Rajasthan) - Childhood-onset recurrent infections These features are classic for trachoma, and Giemsa staining will confirm the diagnosis by demonstrating inclusion bodies. ### Limitations and Alternatives | Investigation | Sensitivity | Specificity | Use Case | | --- | --- | --- | --- | | Giemsa staining | 50–60% | High | First-line in endemic areas | | PCR/NAAT | >95% | >99% | Gold standard (not always available) | | Direct fluorescent antibody (DFA) | 80–90% | High | When Giemsa unavailable | | Inoculation on McCoy cells | 70–80% | High | Research/reference labs | | Serology (IgG) | Low | Low | Not diagnostic for active disease | **Warning:** Serology (IgG) indicates past or present infection but cannot distinguish active from inactive disease and is not diagnostic. **Mnemonic:** **GIFT** — Giemsa staining Is First-line Test for trachoma in endemic areas. 
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