Laboratory event in methotrexate monitoring

Event

Value

Action

Leucopaenia

<3.5*10^9/l

Stop & seek advice

Neutropaenia

<2.5*10^9/l

Stop & seek advice

Thrombocytopaenia

<150*10^9/l

Stop & seek advice

Macrocytosis

>100

Macrocytosis >100 Check B12 and folate

Sequential falls in WCC or PMNs

>10% on occasions

Stop & seek advice

Sequential falls in platelets

Sequential falls >10% on 3 occasions

Stop unless falls are from in platelets from a high level, which is a response to treatment

Elevation of LFTs (AST, ALT, not ALP)

>3x normal

Stop & repeat LFTs (AST, ALT, not ALP) Mild transaminitis is common

Falls in albumin

>5g/l

Stop. Repeat LFTs. (early sign of liver toxicity)