NCLEX Review Guide: Adult Health - Integumentary Diagnostic Tests

Skin Biopsy Procedures

• Punch biopsy involves using a circular blade to remove a small cylindrical section of skin tissue for histological examination. Obtain informed consent and ensure sterile technique to prevent infection.
• Shave biopsy removes superficial skin layers using a scalpel blade parallel to the skin surface, commonly used for raised lesions. Post-procedure care includes applying pressure to control bleeding and covering with sterile dressing.
• Excisional biopsy completely removes the entire lesion with surrounding normal tissue using an elliptical incision. Monitor for signs of infection and dehiscence during healing process.

Skin Scrapings and KOH Preparation

• KOH (Potassium Hydroxide) preparation involves scraping affected skin areas and treating with KOH solution to dissolve cellular material, leaving fungal elements visible. This test specifically identifies dermatophytes, yeasts, and other fungal infections.
• Scabies scraping requires gentle scraping of burrows or papules to identify mites, eggs, or fecal pellets under microscopic examination. Use mineral oil on scalpel blade to prevent specimen from flying away.

Patch Testing for Allergies

• Patch testing involves applying potential allergens to the skin under occlusive patches for 48 hours to identify contact dermatitis triggers. Instruct patient to keep patches dry and avoid vigorous activity that may cause patch displacement.
• Reading results occurs at 48 and 72 hours post-application, evaluating for erythema, edema, vesicles, or bullae formation. Document reaction intensity using standardized grading system (1+ to 4+).

1. Clean test area with alcohol and allow to dry completely
2. Apply allergen patches to upper back in organized grid pattern
3. Mark patch locations with indelible ink
4. Instruct patient on activity restrictions and return appointments
5. Remove patches at 48 hours and read initial results
6. Perform final reading at 72 hours for delayed reactions

Wood's Lamp Examination

• Wood's lamp examination uses ultraviolet light in darkened room to detect fluorescent properties of certain skin conditions and infections. Tinea capitis caused by Microsporum canis produces blue-green fluorescence.
• Erythrasma caused by Corynebacterium minutissimum appears as coral-red fluorescence under Wood's lamp examination. Vitiligo appears as bright white patches with enhanced contrast under UV light.