Table 4 Results from skin prick tests
From: Optimizing diagnostic tests for persulphate-induced respiratory diseases
|  | Hairdressers (n = 19) | Symptomatic controls (n = 12) | Healthy controls (n = 40) |
|---|---|---|---|
Positive control (p/n) | 19/0 | 12/0 | 40/0 |
Negative control (p/n) | 2/17 | 0/12 | 0/40 |
Potassium persulphate (p/n) Conc. (%) | 0/17 | 0/12 | 0/40 |
 2 | – | – | – |
 5 | – | – | – |
 7.5 | – | – | – |
Ammonium persulphate (p/n) Conc. (%) | 0/17 | 0/12 | 0/40 |
 2 | – | – | – |
 5 | – | – | – |
 7.5 | – | – | – |
 10 | – | – | – |
 20 | – | – | – |
Sodium persulphate (p/n) Conc. Â (%) | 0/17 | 0/12 | 0/40 |
 2 | – | – | – |
 5 | – | – | – |
 7.5 | – | – | – |
 10 | – | – | – |
 20 | – | – | – |