Dr Phil Kieran: My daughter is tired all the time — should we check her iron levels? 

Tiredness comes up in about half of my consultations every day, but the most common causes are ones that can be addressed at home. 

"Poor sleep and high stress are the two most common reasons I see for tiredness, and assessing these can be difficult."

My 13-year-old daughter seems tired a lot of the time. I would say she never fully recovered from a virus she picked up last spring. A few friends have suggested that she get blood tests to check for low iron or any other underlying issues. I’m not sure blood tests are necessary, as she is getting up and out to school each day without any issues. What would you suggest?

Tiredness is an incredibly common issue. I would say that about half of all of my consultations every day involve tiredness. While post-viral fatigue is a potential cause, it is generally only a diagnosis that we can make after ruling out more common causes first.

One of the key things I need to do as a GP is figure out whether this is a “normal” amount of tiredness, or whether it’s pathological (being caused by a medical abnormality).

The first step I would take is to see how much this fatigue is impacting your daughter. When we talk about symptoms like tiredness, there are two things to consider: The subjective experience — how tired she feels, how it varies, and how it changes over time — and the objective impact it is having on her life. Does it stop her going to school? Does it stop her playing sport? Does it stop her socialising? Some people feel like I’m challenging them when I ask these specifics, as if I don’t believe their tiredness is a problem, because they push through it to keep going. I can honestly say that this isn’t the case — we need to ask these questions to see what the likely causes are.

Poor sleep and high stress are the two most common reasons I see for tiredness, and assessing these can be difficult.

Anyone who is very tired themselves, or who has a child who is tired a lot of the time, should first look at improving their sleep. Removing screens from bedrooms (including phones), having a regular bedtime and wake-up time, and eating a healthy diet are all very important.

You’ve said that she is managing school every day without issue, and this makes you think blood tests are unlikely to be necessary. I think this is a sensible approach. Blood tests aren’t a magic oracle we can use to make a diagnosis — we can’t, and don’t, just take blood and “test it for everything”. Blood tests show patterns, and we look at whether those patterns, compared with the symptoms we see, actually explain the symptoms. In someone reporting fatigue, I would consider checking iron and thyroid levels, but before I went anywhere with a needle, I would be checking to see if she had any symptoms that pointed towards low iron or an underactive thyroid.

A blood test that doesn’t align with the symptoms is pretty useless.

For your daughter, I would suggest looking first at her sleep habits and making sure she is eating enough iron.

Teenage girls are particularly prone to low iron, especially if she has heavy periods. If things are either getting better or staying the same, I think it’s fair to just observe. But if she starts struggling more with her activities, then I think you need to bring her in to be examined and possibly have blood tests done.