Standard blood tests; tests of organ function

      It is very common for the physician to prescribe a routine selection of "standard" blood tests (or, for the patient, to have one), e.g. during general screening or as an instrument of preventive medicine aimed at the early diagnosis of yet asymptomatic conditions (secondary prevention).
      Standard blood tests may vary somewhat; however they usually include the hemochromocytometric test (the quantitation of red cells, of the various types of white cells and of platelets; hemoglobin concentration), total protein concentration, electrophoretic protidogram, glycemia, azotemia (BUN), creatininemia, transaminases (sGOT, sGPT), bilirubinemia, cholestrolemia, triglyceridemia and possibly other analyses. The general relevance of these routine tests is listed in the Table below.
Measurement Usual range Increases in Decreases in
Hemochromocytometric test
Red blood cells 4.5-6 M/mmc Primary or secondary polycytemia; increased erythropoietin stimuls because of kidney or lung disease Anemias, acute and chronic hemorrages
Hemoglobin 13-17 g/dL see above (polycytemias) Anemias, acute and chronic hemorrages, iron deficiency, vitamin deficiency, thalassemias, etc.
Platelets 150-400 K/mmc uncommon Damage of the bone marrow (e.g. leukemias, lymphomas, idiopathic medullary aplasia)
White cells (total) 4-10 K/mmc Leukemias Damage of the bone marrow (e.g. leukemias, lymphomas, idiopathic medullary aplasia)
White cells formula
Neutrophyle granulocytes 2-8 K/mmc (35-80%) acute bacterial infections; myeloid leukemias bone marrow aplasia; cancer; chemotherapy; autoimmune diseases
Eosinophyle granulocytes 0-800/mmc (0-7%) allergy; parasitic infection  
Basophyle granulocytes 0-200/mmc (0-2.5%) (myeloid leukemias)  
Lymphocytes 1-5 K/mmc (10-50%) (Lymphatic leukemias) (bone marrow aplasia; cancer; some types of infection; autoimmune diseases)
Monocytes 160-1000/mmc (0-12%) (chronic infections; autoimmune diseases) some types of infection; marrow aplasia; glucocorticoid therapy
Hematochemical tests
Glycemia 65-110 mg/dL Diabetes mellitus (type I; type II) insulinoma; excess insulin therapy in diabetic patients
Azotemia (BUN) 10-50 mg/dL any kidney disease causing renal insufficiency  
Creatininemia 0.6-1.3 mg/dL any kidney disease causing renal insufficiency  
Bilirubinemia total 0.3-1 mg/dL (conjugated 0.1-0.3 mg/dL) jaundice; liver disease (increase of unconjugated bilirubin only: hemolytic crisis)  
sGOT < 37 U/L Hepatitis; biliary obstruction; diseases causing the death of liver cells  
sGPT < 55 U/L Hepatitis; biliary obstruction; diseases causing the death of liver cells  
cholesterol total <200 mg/dL Hypercholesterolemia of dietary or genetic origin  
Protidemia total 6-8 g/dL Often due to the gamma globulin fraction (see electrophoresis) decreased biosynthesis because of malnutrition or liver insufficiency; accelerated loss because of severe burn or nephrotic syndrome
Protein fractionation by electrophoresis
Albumin 55-65% (decrease of other components?) malnutrition, liver insufficiency, nephrotic syndrome, severe burn
Alpha 1 globulins 3-5%    
Alpha 2 globulins 7-12%    
Beta 1 globulins 4.5-7%    
Beta 2 globulins 3-6%    
gamma globulins 11-19% Bacterial infections; multiple myeloma (monoclonal peak) Congenital and acquired immunodeficiencies

      Standard blood tests are essential to assess organ functions: indeed, in many cases the physician may suspect a disease affecting a specifci organ, even though he may not have a clue on its cause: e.g. jaundice suggests a defect in liver function, increased azotemia (Blood Urea Nitrogen, BUN) suggests a defect in kidney function, perypheral oedema suggests cardiac failure, etc. Thus organ diagnosis is extremely important and helps focusing a more precise etiological diagnosis. The following table summarizes tests and laboratory evaluations that have been dealt with elsewhere in the course. IN some cases the same test may be applied to more than a single organ or system, and a differential diagnosis is required.
    Organ           typical presenting symptom(s)             functionality tests      
Liver jaundice; dark urine; itch serum bilirubin concentration; transaminases
Lung and respiratory tree dispnoea; cyanosis; fatigue hemogas analysis; measurement of respiratory volumes; measurement of pulmonary blood flow
Kidney increased BUN; confusive state; hypertension BUN; glomerular filtration rate (creatinine clearance)
Heart perypheral oedema; dispnoea; altered blood pressure; altered pulse; thoracic pain; abnormal heart sounds determination of central venous pressure; determination of LDH, CPK and other typical heart enzymes; measurement of pulmonary blood flow; ECG; echography
Bone marrow anemia, pallor, fatigue, petechiae hemochromocytometric analysis; marrow biopsy

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