What are the sensitivity and the specificity of a normal measurement of non-specific reactivity while at work in the diagnosis of occupational asthma?

The following references have been associated with this question by users of this website. They do not form part of the BOHRF occupational asthma guidelines.

burgeps	Labrecque 2004	1/2 workers with positive challenge had normal NSBR before and after challenge (but no very recent exposure before the challenge) An extract of pork mean illicited an immediate asthmatic reaction in one, the other had a positive workplace challenge
burgeps	Hannu 2007	Sensitivity 71% against specific challenge
burgeps	Beach 2007	Non-specific hyper-responsibeness sensitivity 79.3% (68-88) High MW;66.7% (58-74) Low MW. Specificity 51.3% (35-67) high MW, 63.9% (56-71) Low MW
burgeps	Yacoub 2007	1/40 had normal methacholine reactivity (>16mg/ml at diagnosis)
burgeps	Dufour 2009	The individual sults of NSBR e not given, but the mean methacholine Pc20 was 3.5 mg/ml (0.02-112) ffor low w allegens pre challenge and 2.7 mg/ml (0.04-128) or high mw agents The cchages post challege wwere sall (LMW 1.8 +/- 2.3, HMW 0.8 +/- 1.8). The changes following immediate reactions (were lower than those following late reations as expected) but only for high MW agents
burgeps	Munoz 2004	sensitivity 75%, specificity 12.5%
burgeps	Sauni 2010	Study of cobalt asthma in a refinery with cases defined by specific inhaltion challenge to cobalt dust. Normal NSBR in 5/22 (23%) at diagnosis
burgeps	Malo 2011	This is an interesting paper, but all the analysis is retrospective and requires prospective validation. Although there was a relationship between sputum eosinophilia, NSBR and occupatiuonal asthma both together and separately, the negative combination is not enough to exclude occupational asthma (negative predictive value 58% when compared with non-occupational asthma. NSBR (methacholine >16mg/ml) normal in 35/129 challenge positive oa
burgeps	Labrecque 2011	42% of the 22 with challenge positive OA had normal NSBR (interval from last exposure not stated)
burgeps	Beretta 2017	Methacholine >16mg/ml in 13% of a predominantly high MW group
burgeps	Engel 2019
burgeps	Lipinska-Ojrzanowska 2020	Normal NSBR was found pre SIC in 45% of reactors to high molecular weight allergens and 19% reactors to low MW agents. A 3 fold increase in NSBR followed LMW reactors in 83% and High MW reactors in 66%.
burgeps	Abramson 2020	Pre-employment increase non-specific reactivity was not predictive of future occupational asthma symptoms or accelerated FEV1 loss in aluminium foundry workers and was not recommended