110A score reflecting impairment from asthma is calculated by:

110     A score reflecting impairment from asthma is calculated by:

a)      adding the points scored for reduction in FEV1 %P;

and either

i)        change in FEV1 with bronchodilator (reversibility);

or

ii)      degree of bronchial hyperreactivity defined by the cumulative dose of metacholine, or histamine, required to decrease baseline FEV1 by at least 20%;

and

b)      measurement of FEV1, or peak flow (PF) rate, measured by the employee morning and evening, before and after aerosol bronchodilator, for at least 30 days.

111     The number of days on which any valid measurement of FEV1 or PF is less than 0.85 x the mean of the six highest values of FEV1 or PF during the monitoring period is to be expressed as a percentage of total days in the monitoring period.

112     The maximum impairment score from Figure 2-A: Calculating asthma impairment score is 11. One additional point is given, yielding a score of 12, if asthma cannot be controlled adequately with maximal treatment. The score from Figure 2-A is converted to a WPI rating using Table 2.2: WPI derived from asthma impairment score.

Figure 2-A: Calculating asthma impairment score

See notes to Figure 2-A for further information.

| Score | FEV1, % P after bronchodilator | FEV1, % change in FEV1 with bronchodilator | PD20 or µmol | % of days lowest FEV1* is ≤0.85 highest FEV1 | | 0 | >85 | <10 | >4.0 | <6 | | 1 | 76 to 85 | 10 to 19 | 0.26 to 4.0 | 6 to 24 | | 2 | 66 to 75 | 20 to 29 | 0.063 to 0.25 | 25 to 34 | | 3 | 56 to 65 | ≥30 | ≤ 0.062 | 35 to 44 | | 4 | ≤55 | | | ≥45 |

Notes to Figure 2-A

1. Figure 2-A is based on scales proposed by: the American Thoracic Society (1993), as adapted in Tables 5-9 and 5-10 of the AMA5; and the Thoracic Society of Australia and New Zealand (Abramson, 1996).

2.     %P = percent predicted normal value.

3.     PD20 = cumulative dose of inhaled metacholine aerosol causing a 20% decrease in FEV1.

4.     * monitored twice daily before and after aerosol bronchodilator for at least 30 days during adequate treatment.

5.     % of days = proportion of days any value of FEV1 (or of peak flow rate) is less than highest repeatable FEV1 (or peak flow rate) x 0.85.

Table 2.2: WPI derived from asthma impairment score

| %WPI | Asthma impairment score | | 0 | 0 | | 10 | 1 | | 20 | 2 | | 30 | 3 | | 40 | 4 | | 45 | 5 | | 50 | 6 | | 55 | 7 | | 60 | 8 | | 65 | 9 | | 70 | 10 | | 75 | 11 | | 80 | 12 |

2.3        Lung cancer and mesothelioma