Hi all, I'm new to this forum and in the middle of study for Step 1. Took the form 1 on friday and am going over my answers...I found a bit of a contradiction in a question regarding hereditary angioedema. The question (paraphrased to protect copyright ): Young girl with an acute onset of facial swelling and dyspnea. Hereditary Angioedema is suspected (C1 esterase inhibitor), what will be found in serum? 1. Decreased serum C4 2. Increased serum properdin 3. Normal C1q 4. Normal C1s 5. Normal C2 In a bit of research I found out that: So here...answers 1 and 3 could be true? I could be totally off but does anyone have an answer?