What does low C3 level in blood test mean?

Just received my latest blood results over the phone and been told that my C3 level is below normal so need to come into the surgery on Monday morning to see my GP. Does anyone know what this means or what causes it to be low? Should I be concerned?! I have been feeling incredibly tired this week with bouts of dizziness and nausea. Wondering if it's connected.

Any advice will be gratefully received :)



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8 Replies

  • Hi belee, sorry to disappoint, but someone posted yesterday about C4 bloods. Have never heard of either, so hoping someone can enlighten me, and you. !!!!! Hope it's nothing too much to worry about for you.

  • It is rather complicated to explain so I assume you GP will want to do this. You may want to look on wikipedia at 'Complement' and follow that up by looking at the lab tests online website athttp://www.labtestsonline.org.uk/understanding/analytes/complement-levels/tab/faq

  • Thank you, that has helped. Xxx

  • Hi there

    They may want to do further tests. My compliment gets lower than normal due to disease activity. If you're feeling dizzy and tired this might make sense and may point to that, so they may do further tests or send you to the rheumatology clinic to get checked out.

    Good luck.

  • Thank you for your reply. My surgery has just phoned this morning having arranged a rheumatology appointment for me for Monday morning so I guess things will be clearer then!


  • Ah good luck for your appointment.

  • Hi Belee

    I often have low C3 and C4 levels and this basically means that the SLE is active and it does usally tie in with a relapse. I tend not to have many of the other markers but I do have the C3 and C4 markers everyone is different. Wiki gives a useful explaination. However, if you have been feeling particularly fatigued and nauseas as you describe then I think your low C3 is telling you that your disease is active I am sorry to say, so rest up. Mx

  • Thanks cloggy73, am resting as we speak ;) xxx

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