What tests are needed for psoriasis patients before receiving biologic injections?

Before receiving biologic agents, psoriasis patients generally need to undergo several tests, including infectious disease screening, complete blood count (CBC), liver and kidney function tests, inflammatory marker assessments, and tuberculin skin testing. If any abnormalities are found, prompt medical consultation is recommended. Specific details are as follows:

1. Infectious disease screening: Includes testing for hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV). Biologic agents may affect immune function; if an infection is present, treatment could lead to reactivation or worsening of the infection. Pre-treatment screening helps avoid such risks.

2. Complete blood count (CBC): Evaluates red blood cells, white blood cells, platelets, and other parameters. This test helps determine whether the patient has conditions such as anemia, leukopenia, or platelet abnormalities. If abnormal results are detected, the patient's health status should be stabilized first before assessing suitability for biologic therapy.

3. Liver and kidney function tests: Includes assessment of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and blood urea nitrogen (BUN). Some biologic agents are metabolized by the liver or excreted through the kidneys. Impaired liver or kidney function may alter drug metabolism and increase the risk of adverse reactions. These tests help guide the development of safe medication plans.

4. Inflammatory marker assessments: Primarily involves measuring C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). These markers reflect the level of systemic inflammation, helping physicians evaluate disease activity, determine the necessity and timing of biologic treatment, and provide baseline data for monitoring therapeutic response.

5. Tuberculin skin test: Involves injecting tuberculin and observing the skin reaction to assess possible infection with *Mycobacterium tuberculosis*. Biologic agents may reduce immune defenses and reactivate latent tuberculosis infections. This test can identify existing TB infections in advance, preventing serious complications after starting treatment.

Patients must complete all required tests under the guidance of a physician and should not omit or skip any examination arbitrarily. Prior to testing, patients should follow medical instructions for proper preparation, such as fasting and avoiding strenuous exercise.