C‑reactive protein is the classic acute phase protein in inflammatory reactions. It is synthesized by the liver and consists of five identical polypeptide chains that form a five‑membered ring having a molecular weight of 105000 Daltons. CRP is the most sensitive of the acute phase reactants and its concentration increases rapidly during inflammatory processes. Complexed CRP activates the classical complement pathway. The CRP response frequently precedes clinical symptoms, including fever. In normal healthy individuals CRP is a trace protein with a range up to 5 mg/L. After onset of an acute phase response the serum CRP concentration rises rapidly and extensively. The increase begins within 6 to 12 hours and the peak value is reached within 24 to 48 hours. Levels above 100 mg/L are associated with severe stimuli such as major trauma and severe infection (sepsis). CRP response may be less pronounced in patients suffering from liver disease. CRP assays are used to detect systemic inflammatory processes; to assess treatment of bacterial infections with antibiotics; to detect intrauterine infections with concomitant premature amniorrhexis; to differentiate between active and inactive forms of disease with concurrent infection, . in patients suffering from SLE or Colitis ulcerosa; to therapeutically monitor rheumatic disease and assess anti - inflammatory therapy; to determine the presence of post‑operative complications at an early stage, such as infected wounds, thrombosis and pneumonia, and to distinguish between infection and bone marrow rejection. Postoperative monitoring of CRP levels of patients can aid in the recognition of unexpected complications (persisting high or increasing levels). Measuring changes in the concentration of CRP provides useful diagnostic information about how acute and how serious a disease is. It also allows judgements about the disease genesis. Persistence of a high serum CRP concentration is usually a grave prognostic sign which generally indicates the presence of an uncontrolled infection.
In iron deficiency anemia (microcytic-hypochromic=decreased Hemoglobin), iron stores are depleted prior to anemia; therefore, the earliest change observed is usually decreased ferritin. Hemoglobin: Normal (female): 12-16 g/dL ; Male 14-18 g/dL. Hematocrit: Normal (female): 35-40% ; (Male): 42-52%. A low Hematocrit indicates a decrease in number or size of RBC or increase in plasma volume. RBC count: to 6 million/ml (4 to female). MCV(mean corpuscular volume): indicates microcytic, normocytic or macrocytic morphology. MCH(mean corpuscular hemoglobin): Average weight of Hgb in RBC. Decreased in microcytosis and hypochromia(low hgb). MCH alone cannot distinguish between the two. MCHC(mean corpuscular hemoglobin conc.): (Nml: 31-36%): weight of Hemoglobin/volume of cells. Independent of cell size and, therefore, is more useful than MCH in distinguishing between microcytosis and hypochromia. A low MCHC always indicates hypochromia, as a microcyte with a normal Hemoglobin concentration will have a low MCH but a normal MCHC. Red cell distribution width (RDW): Normal: - % Indicates how much the RBC's vary in size. Elevated in anemia's resulting from nutritional deficiencies (iron,folic acid, B12). Serum iron concentration: concentration of iron bound to transferrin. Unfortunately, the serum level of many patients with iron deficiency anemia remains within the lower limits of normal. There is a 20-30% diurnal variation in serum iron levels--it is best to draw levels in the morning. Total iron binding capacity (TIBC): indirect measurement of serum transferrin. Unlike the serum iron level, the TIBC is remarkably constant. The finding of a low serum iron and a high TIBC indicates iron deficiency anemia. Serum ferritin: the concentration of ferritin (storage iron) in the serum is proportional to total iron stores. Low ferritin levels are virtually diagnostic of iron deficiency anemia as they are decreased only in iron deficiency anemia. Liver disease causes an elevation in serum ferritin; thus ferritin should not be used for diagnostic purposes in patients with even mild hepatic pathology.