How to interpret PPD (Purified Protein Derivative) results?
Rahul's Noteblog Notes on Bacteriology How to interpret PPD (Purified Protein Derivative) results?
NOTE: A PPD is read as the greatest area of induration, not erythema.
Induration greater than 5 mm induration is considered positive in:
• HIV-positive individuals.
• Individuals with recent contact with a TB-positive person.
• Individuals with signs of TB on chest x-ray.
• Organ transplant patients, patients with immunosuppressive therapy.
Induration greater than 10 mm induration is considered positive in:
• Individuals who recently emigrated from a developing country.
• Injection drug users.
• Residents or employees of high-risk settings - prisons, homeless shelters, hospitals.
• Patients with diabetes, chronic kidney disease, hematologic malignancies, or fibrotic lung disease.
• Children younger than 4 years old and teens exposed to high-risk adults.
Induration greater than 15 mm induration is considered positive in:
• Healthy individuals with no risk factors for TB infection.
Additional Readings:
Basic Bacteriology
1. Bacterial Locations and Toxins
2. Growth Medias and Oxygen Requirements
3. Staphylococus
4. Streptococcus
5. Enterococcus
6. Bacillus
7. Listeria
8. Corynebacterium
9. Actinomyces
10. Nocadria
11. Mycobacterium
12. Clostridium
13. Neisseria
14. Pseudomonas
15. Legionella
16. Bordetella
17. Francisella
18. Brucella
19. Campylobacter
20. Escherichia
21. Shigella
22. Klebsiella
23. Salmonella
24. Yersinia
25. Proteus
26. Vibrio
27. Pasteurella
28. Haemophilus
29. Bacteriodes and Prevotella
30. Treponema
31. Borrelia
32. Rickettsia
33. Coxiella
34. Ehrlichia
35. Chlamydia
36. Mycoplasma
37. What is an ELEK's Test?
38. Causes of Orchitis
39. What is Leprosy?
40. What is Folliculitis?
41. What is Botulism?
42. How to interpret PPD (Purified Protein Derivative) results?
43. Prenatal Infections
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1. Bacterial vs viral infections
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