From the Guidelines
A blood test for hives workup should include a complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), thyroid function tests, and liver function tests, as these tests help identify underlying causes such as infections, autoimmune disorders, thyroid disease, or allergic reactions that might be triggering the hives 1.
Initial Testing
The initial testing for hives should be guided by the patient's clinical history and physical examination findings.
- A complete blood count (CBC) to rule out infections or blood disorders
- Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to assess for inflammation
- Thyroid function tests to evaluate for thyroid disease
- Liver function tests to assess for liver damage or disease
Additional Testing
Additional specific tests may be necessary based on the patient's symptoms and clinical findings, including:
- Antinuclear antibody (ANA) to evaluate for autoimmune disorders
- Complement levels (C3, C4) to assess for complement deficiencies or disorders
- Tryptase levels to evaluate for mast cell disorders
- Specific IgE antibody tests to identify allergic triggers
Chronic Hives
For patients with chronic hives, testing for autoimmune markers like anti-thyroid antibodies and anti-FcεRI (high-affinity IgE receptor) antibodies may be performed 1. It's essential to note that in about 80-90% of chronic hives cases, no specific cause is identified despite testing, which is called chronic spontaneous urticaria 1. The healthcare provider will determine which specific tests are appropriate based on the patient's symptoms, duration of hives, and other clinical factors.
Disease Control Assessment
The Angioedema Control Test (AECT) and the Urticaria Control Test (UCT) are validated instruments for measuring disease control in patients with chronic spontaneous urticaria (CSU) and angioedema 1. These tests can help guide treatment decisions and assess the effectiveness of therapy. The AECT is used to quantify disease control in patients with CSU with angioedema, while the UCT is used to assess disease control in patients with CSU who develop wheals with or without angioedema. The cutoff for well-controlled disease is 10 points for the AECT and 12 points for the UCT. These tests are easy to administer and can be used to monitor disease control over time.
From the Research
Blood Test for Hives Workup
- The workup for hives may involve blood tests to rule out underlying inflammatory conditions, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) 2, 3, 4.
- ESR and CRP are markers of inflammatory conditions and can be used to monitor chronic inflammatory conditions, as well as diagnose and monitor responses to therapy in acute inflammatory conditions 2, 3.
- CRP is a better indicator of inflammation than ESR, as it is more sensitive and responds more quickly to changes in the clinical situation 4.
- Factors such as age, sex, and renal disease can affect ESR and CRP levels, and false negative and false positive results can occur 4, 5.
- In patients with no known inflammatory conditions, discordant patterns between ESR and CRP can be associated with age and body mass index (BMI) 5.
- ESR and CRP can be used to aid in the diagnosis and monitoring of various medical conditions, including acute and chronic diseases 6.
- Elevated ESR and CRP levels can be seen in both acute and chronic medical conditions, and there is no significant difference between the two markers in terms of their association with acute versus chronic medical conditions 6.