Serum Total Protein and Visceral Protein Status

Protein Status Assessment

• Serum total protein is used as an index for protein status, but it's not a sensitive index and can be affected by various factors.
• Serum albumin is a classical test for assessing protein status, but it's not very sensitive for short-term changes and can be affected by confounding factors such as gastrointestinal disorders, renal diseases, and liver failure.

Serum Albumin

• Synthesized in the liver, albumin maintains colloidal oncotic pressure and transports proteins.
• Affected by other confounding factors such as gastrointestinal disorders, renal diseases, and liver failure.
• Low albumin levels can indicate prolonged protein deficiency, while high levels can indicate semi-starvation state and dehydration.

Serum Transferrin

• Synthesized exclusively in the liver, transferrin is an iron transport protein.
• Half-life is 8-10 days, and it's a negative acute-phase respondent.
• Increases when iron stores are depleted, and affected by iron status and protein-energy malnutrition (PEM) status.
• Not suitable for monitoring protein status in intervention studies due to poor response to dietary treatment.

Transthyretin (Pre-Albumin)

• A transport protein for thyroxine and retinol-binding protein.
• Half-life is 2-3 days, making it more sensitive than serum albumin and transferrin in monitoring improvements in protein-energy status.
• Affected by other confounding factors such as gastrointestinal diseases, renal diseases, trauma, stress, and infections.

Retinol-Binding Protein

• A carrier protein of retinol.
• Half-life is 12 hours, and it's a negative acute-phase protein.
• Sensitive to protein status but less sensitive to energy status.
• Responds rapidly to dietary treatment.

Nitrogen Balance

• Nitrogen balance = nitrogen intake (g/24 hours) – urinary nitrogen (g/24 hours) + 2 (g/24 hours).
• Nitrogen balance is positive in growing children, pregnant women, and adults gaining weight or recovering from illness or injury.
• Nitrogen balance is negative during starvation, catabolism, and PEM.

Acute Phase Protein

• C-Reactive Protein (CRP) is synthesized in the liver and has a half-life of 5-7 hours.
• May increase within 4-6 hours of stress, inflammation, or trauma.
• Decreases when stress subsides.

Assessment of Nutritional Anemia

• Common causes of nutritional anemia include low intake of iron and folate, increased requirements, and increased losses due to infections.
• Types of anemia include normocytic normochromic (anemia of chronic diseases), microcytic hypochromic (iron deficiency anemia), and macrocytic normochromic (folate or B12 deficiency anemia).

Iron in the Body

• Transferrin is a transport protein for iron and a negative acute-phase protein.
• Hemoglobin contains 70% of body iron, mainly in red blood cells.
• Storage iron (ferritin) is 25% of body iron, mainly in the liver, spleen, and bone marrow.

Stages of Iron Deficiency

• Depletion of iron stores
• Iron deficient erythropoiesis
• Iron deficiency anemia

Assessment of Nutritional Anemia

• Hemoglobin (Hb) is the most widely used test for iron deficiency anemia, but it's not a good indicator for early iron deficiency.
• Hematocrit represents packed cell volume (PCV) and is easy to measure, but it's not sensitive for early iron deficiency.
• Mean cell volume (MCV) is a specific index for iron deficiency anemia, while mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC) are less useful indicators.