The ampersand character (&) used in normal everyday grammar is shorthand for the word and or in Latin “et”. In LOINC , it is used mostly in the Analyte axis where it is surrounded by spaces, e.g. Acetaldehyde & Paraldehyde panel.  As a panel term, it is linked to two separate result codes, one for Acetaldehyde and one for Paraldehyde. This panel would carry a combined but separately measured result. In other words, analytes mentioned together via the ampersand (&) in the LOINC name can be detected and differentiated.

Here are the 2 Result codes connected to this LOINC:

The plus sign (+), while a cousin of the ampersand (&) in terms of everyday meaning, is treated differently in LOINC. The plus sign (+) is used (without spacing before or after) when two or more components of the Analyte axis are measured as one quantity, e.g., Imipramine+Desipramine. In other words, analytes using the plus sign (+) can be detected, but they will not be differentiated – they will be reported as a single result.

Here’s an interesting example that uses both the plus sign (+) the ampersand (&) – there are two results reported:  HIV 1/2 antibodies and HIV-1 p24 antigen.

Quick summary: “&” in LOINC means two or more constituents in the Analyte axis are to be detected and differentiated, while “+” means two or more constituents are to be detected but have a combined result (undifferentiated).
We hope this is an interesting LOINC hack for you. If you have other terminology hacks that you’d like to share or need help with terminology mapping , please contact us .