Question: When you find an unusual sample that requires more analysis - what other tests would you carry out to find out further results?

Emma Ashley answered on 20 Mar 2013:

It depends on what the unusual result was. Often we have a ‘first line’ test and if this is abnormal we go onto check for other things. I’ve got lots of examples –

If a patient had a low calcium level in their blood, you would check their magnesium level as magnesium is needed for the absorption of calcium from the gut. If magnesium is low, then that could explain the low calcium. It is important to keep you calcium at a certain level because it is needed for muscle contraction. You could aso measure vitamin D as this is needed for calcium homeostasis.
If the patient is anaemic (low levels of red blood cells), and they are smaller than normal, you would test the patient’s iron stores to see if they are deficient. If the red blood cells are bigger than normal, you would measure vitamin B12 and folate levels to see if the patient is deficient in these vitamins.
If a patient was finding it difficult to get pregnant, you would measure their hormones (progesterone, LH, FSH). If these were normal, you would then test more hormones for other causes of infertility.

A really good website to look at is labtestsonline.org.uk. It gives you loads of information on all the tests that we measure in the lab and what the results mean.