Table: mathematical signs and symbols

+ plus
minus
÷ divided by
× multiplied by (‘times’)
= equals
not equal to
> greater than (ie >500 means ‘more than 500′)
greater than or equal to (ie ≥500 means ’500 and over’)
< less than
less than or equal to
~ approximately
± plus or minus – this is use to show the range of group of values (Standard Deviation) when the mean is used to calculate the average, eg SD ± 0.45.
% percentage
n number (in a statistical sample, eg n=16 means 16 results, people etc)

Table: Greek characters

α alpha or alfa a
β beta b
Δ δ delta d – this is the abbreviation for ‘change
γ gamma g
μ mu m – this is the abbreviation for ‘micro’ eg µL = micro litre

Greek letter are commonly used for names of immune-related chemicals, ie interferon-alpha (IFN-a, IFN-α) or interferon-beta (INF-b, IFN-β) to treat hepatitis C.

Delta is used as a short cut for ‘change’, ie delta CD4 (ΔCD4 or δCD4) means ‘change in CD4′.

Table: medical abbreviations

qd or QD once daily
bd or BD or BID twice daily
td or TD or TID three times daily
q12h or q12H every 12 hours
q24h or q24H every 24 hours
Bx biopsy
Dx diagnosis, diagnosed
Px problem, symptom (P = patient)
Rx prescription or resistance
Tx treatment

Last updated: 22 July 2009.