Males <60yrs : <85ng/L
Male ≥60yrs: <161ng/L
Female < 60yrs: <144ng/L
Female ≥ 60yrs: <203ng/L
Heart failure referral guidelines (NICE):
<400 ng/L: do not refer
400-2000 ng/L: Refer within 6 weeks
>2000 ng/L: Refer urgently (<2 weeks)
Provided by referral laboratory