Z scores - cardiology

[Madsometimes]

A bit of a long shot, but I know MNers know about some strange things. I'm also not sure if here or children's health is the right place to post.

When my dd goes for her echos, her cardiologist focuses in on z scores for aorta diameters. I know that z scores relate the measurements taken to the average distribution for people with her body surface area. I think they place her on a centile, similar to a standard growth chart for height or weight, but this is where I get fuzzy.

Does anyone know what a totally average z score is? Is it 0? Her last z scores were about 2.4. The cardiologist said that they were increasing and outside the normal range. He didn't start medication although said it would be needed soon.

Obviously, I will ask him to explain what these scores mean at the next appointment, but in the meantime if anyone can explain this without resorting to statistics 101 it would be unexpected but very nice.

I don't know anything about the medical aspects of your query, but statistically, yes, 0 represents the Group mean (average), a positive number is greater than the group mean, and a negative number would be lower than the group mean. Remember that this is based on a statistically normal distribution of measurements, so actually more people will have a number higher or lower than the group mean them will actually have zero.

Sorry, that should be 'than' will have zero.

Thanks very much for your reply. I feel much more confident now that I understand what these scores mean. She's around the 99th centile, so it does seem that medication will be given, unless her pattern of growth has changed (very unlikely).

I always feel more confident dealing with HCP's when I can decipher what it is they are talking about.