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Serum Total Protein estimation

Q.1- What is the normal range of serum total proteins? What is A: G ratio?

 Answer- The total plasma protein concentration normally ranges between 6.0 to 8.0 G/dl. Albumin ranges between 3.5 to 5.5 G/dl and Globulins range between 2.5-3.5G/dl . The ratio of albumin to Globulin concentration is called A: G ratio and it varies from 1.5-2.5:1.

 Q.2 – What are the causes of hypoproteinemia?

 Answer- Hypoproteinemia,i.e., a generalized decrease in plasma proteins occurs in –

 (1) Liver diseases,because hepatic protein synthesis is depressed (Mainly albumin is low)

 (2) Renal disorders like the Nephrotic syndrome, in which glomerular membrane permeability increases markedly.

 (3) Malnutrition and starvation- reduced dietary availability

 (4) Protein-losing enteropathy- excessive loss through intestine

 (5) Wide spread burns- loss from skin

 (6) Severe hemorrhage- increased protein catabolism

 (7) Defective digestion or malabsorption as in carcinoma of stomach or pancreas, peptic ulcer and steatorrhea.

 (8) Fever- increased protein catabolism

 (9) Pregnancy-hemodilution and increased requirement

 (10) Acute infections in-untreated diabetes mellitus and hyperthyroidism

 Q.3- What are the causes of hyperproteinemia?

 Answer- Increase in plasma proteins are seen in

 (1) Acute inflammatory states. Several plasma proteins increase sharply during any acute inflammation. These are called acute phase proteins. They include C-reactive proteins (CRP), so-called because it reacts with C- polysaccharide of pneumococci.

(2) Multiple myeloma. In this condition, the plasma cells secrete large amounts of immunoglobulin resulting in hypergammaglobulinemia

(3) Dehydration –due to hemoconcentration

 (4) Chronic infections

 (5) Leukemias

 (6) Lymphomas

 (7) Tuberculosis

 (8) Kala Azar

 (9) HIV infection

 Increase in plasma protein concentration is generally due to an increase in total globulins (Gamma globulins) and the concentration of albumin remains the same or decreases marginally. A decrease in total protein concentration is due to fall in albumin and some times globulins. In these conditions A:G ratio changes due to either reduction of Albumin or increase of Globulins.

 Q.4-What is the effect of plasma volume on total protein concentration?

 Answer- Decrease in the volume of plasma water –Hemoconcentration, is reflected as relative hyperproteinemia and the concentration of all individual plasma proteins are increased to the same degree.

Hyperproteinemia is observed in dehydration due to-inadequate water intake or due to excessive water loss as in –Diarrhea, vomiting, Addison’s disease, diabetic ketoacidosis and diabetes Insipidus.

 Hemodilution occurs with water intoxication and salt retention syndromes, during massive intravenous infusions and physiologically when a recumbent position is achieved. A recumbent position decreases plasma protein concentration by 03-0.5 G/dl. In hemodilution individual plasma proteins are decreased by the same degree.

 Q.5- What are the functions of plasma proteins?

Answer- Functions of the plasma proteins include:

  • Intravascular osmotic effect for maintaining fluid and electrolyte balance
  • Contribute to the viscosity of the plasma
  • Transport of insoluble substances around the body by allowing them to bind to protein molecules. Blood plasma proteins like albumin functions as carrier proteins that help in the translocation of different biomolecules in body.
  • Protein reserve for the body
  • Clotting of blood
  • Inflammatory response
  • Protection from infection- The gamma globulins function as antibodies
  • Maintenance of the acid-base balance
  • Blood plasma contains the protease inhibitor enzymes like alpha-1 antitrypsin that help in the reduced proteolytic activity in the blood.

Q.6-What is the cause of hyperproteinemia in cirrhosis of liver or other liver disorders?

 Answer-Although the concentration of serum Albumin is reduced in severe liver diseases (Since albumin is synthesized in liver), that of globulins is usually increased (For compensation as they are synthesized in spleen and bone marrow) so that the total plasma protein concentration is rarely low and is often high.

 Q.7- What is the cause of edema in hypoproteinemia?

 Answer- Plasma proteins contribute to plasma colloidal osmotic pressure, counteracting the effects of capillary blood pressure, which tends to force water in to tissue spaces. The lowered plasma protein concentration causes a decrease in the plasma osmotic pressure and water is forced in to tissue spaces resulting in edema. Edema is probable when the albumin concentration falls below 2G/dl.

 Q.8- State your diagnosis from the following Blood and Urinary findings

Biochemical Parameter   Patient 1                         Patient 2

Blood                             Hypoproteinemia                  Hypoproteinemia

Urine                              Proteinuria                                 Normal Urine                          

Answer-Patient 1- With Hypoproteinemiaand proteinuria is most probably suffering from Nephrotic syndrome, while Patient 2 with hypoproteinemia without proteinuria might be suffering from Kwashiorkor.

 Q.9- What is Nephrotic syndrome? What are the laboratory findings in this syndrome?

Answer-Nephrotic syndrome(NS), also known as Nephrosis, is defined by the presence of nephrotic-range proteinuria, edema, hyperlipidemia, and hypoalbuminemia. 

In a healthy individual, less than 0.1% of plasma albumin may traverse the glomerular filtration barrier.Nephrotic-range proteinuria in adults is characterized by protein excretion of 3.5 g or more per day.

 Biochemical basis

1) An increase in glomerular permeability leads to albuminuria and eventually to hypoalbuminemia. In turn, hypoalbuminemia lowers the plasma colloid osmotic pressure, causing greater trans capillary filtration of water throughout the body and thus the development of edema.

2) In the nephrotic syndrome, levels of serum lipids are usually elevated. This can occur via (i) hypoproteinemia that stimulates protein,including lipoprotein, synthesis by the liver, and (ii) diminution of lipid catabolism caused by reduced plasma levels of lipoprotein lipase.

 Laboratory findings

1) Urinalysis- Proteinuria is observed

2) Blood chemistries

i) Serum total and differential protein- A decreased serum albumin (< 3 g/dL) and total serum protein less than 6 g/dL may be observed.

ii)-Lipid Profile-Hyperlipidemia occurs in over 50% of those with early nephrotic syndrome. The degree of hyperlipidemia increases with the degree of protein loss.

iii) ESR and Serum Fibrinogen levels-Patients can have an elevated erythrocyte sedimentation rate as a result of alterations in some plasma components such as increased levels of fibrinogen.

iv) Renal Function Tests- BUN (Blood urea nitrogen) and serum creatinine rise in the setting in of renal failure.

v) Renal biopsy- For confirmation of diagnosis

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