Routine Lab Tests

• Can you mention some of routine Lab tests? – CBC – Blood group(esp. for surgical patients) – U/A – serum electrolytes , ------

CBC

• The complete blood count (CBC) is a common blood test that evaluates the three major types of cells in the blood:

• red blood cells, • white blood cells, and• platelets.

Ctd.

A CBC may be ordered as part of a• routine checkup, or • if your child is feeling more tired than usual, • seems to have an infection,• or has unexplained bruising or bleeding.

Red blood cells • The CBC's measurements of red blood cell (RBC) count

includes:• hemoglobin (the oxygen-carrying protein in RBCs),• Hct:The hematocrit (Ht or HCT) or packed cell volume (PCV)

or erythrocyte volume fraction (EVF) is the proportion of blood volume that is occupied by red blood cells

• red cell indices MCV,MCH,MCHC

• MCV=HCT/RBC, NV = 83 to 97 fL

• MCHC=HGB/HCTNV 31 to 34 g/dL

• MCH=HGB/RBC, NV 28 to 32

Red blood cells

• provides information about the RBCs, which carry oxygen from the lungs to the rest of the body

• These measurements are usually done to test for anemia, a common condition that occurs when the body has insufficient red blood cells.

White blood cells

• The white blood cell (WBC) count measures the number of WBCs (also called leukocytes) in the blood.

• The WBC differential test measures the relative numbers of the different kinds of WBCs in the blood.

• Polymorphs( neutrophils) : react within an hour of tissue injury and are the hallmark of acute inflammation

• Lymphocytes: play an important and integral role in the body's defenses.

• Monocytes: part of the human body's immune system , in response to inflammation signals, monocytes can move quickly (aprox. 8-12 hours) to sites of infection

• Eosinophils:They also control mechanisms associated with allergy and asthma

• Basophils: allergies and parasitosis

• WBCs, which help the body fight infection, are bigger than red blood cells and there are far fewer of them in the bloodstream.

An abnormal WBC count may indicate• an infection, • inflammation, or• other stress in the body. • For example, a bacterial infection can cause

the WBC count to increase, or decrease, dramatically

Platelets

• The smallest blood cells, platelets play an important role in blood clotting and the prevention of bleeding.

• When a blood vessel is damaged or cut, platelets clump together and plug the hole until the blood clots...

• If the platelet count is too low, a person can be in danger of bleeding in any part of the body..

The CBC can also test for• loss of blood, • abnormalities in the production or destruction

of blood cells, • acute and chronic infections, • allergies, and• problems with blood clotting

The Procedure

• Not much blood is drawn in a CBC. A health professional will usually draw the blood from a vein.

• For an infant, the blood may be obtained by puncturing the heel with a small needle.

• If the blood is being drawn from a vein, the skin surface is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

• A needle is inserted into a vein (usually in the arm inside of the elbow or on the back of the hand) and blood is withdrawn and collected in a vial or syringe.

• After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. The entire test will only take a few minutes.

Normal values• Hgb wbc N L M E p • At birth 13.7-20 9-30 61 31 6 2 150-450

• 2 wk 13-20 5-20 40 48 9 3 • 1 m 10-14 5-19 35 56 7 3 • 6 m-6 y 10.5-14 6-17 32 61 5 3 • 7-12 y 11-16 5-14 51 42 5 3 • adult• female 12-16 4-13 57 35 5 3 • male 14-18

Blood Chemistries

• Blood chemistries refers to an analysis of a number of chemical substances in the blood, having clinical significance

Cardiac Enzymes

• CPK • AST • LDH

Liver Function Tests

Kidney Function Tests

Electrolytes

• Calcium • Chloride • Phosphorus • Magnesium • Potassium • Sodium

Lipid profiles

• Cholesterol • Total • LDL • HDL • VLDL • Triglycerides

Coagulation profile

• CBC • Platelets • Prothrombin Time(PT) • Partial thromboplastin time(PTT) • Bleeding time

Hormonal asseys

• Pregnancy test • T3 and T4• TSH • FSH • LH • Prolactin • Estradiol • DHEAS (Dehydroepiandrosterone sulfate

• Glucose• CO2 Content • Uric Acid • CPK • LDH

Liver function tests

•

Primary functions of the liver

• Bile production and excreation• Excreation of bilirubin, cholestrol,hormones

and drugs• Metabolism of fats, proteins,and

carbohydrates• Storage of glycogen , vitamins,and minerals

and regulation of glucose levels

• Synthesis of plasma proteins,such as albumin and clotting factors

• Blood detoxification and purification• Conversion of ammonia into a less toxic form

called urea

• A/G Ratio ( normal is 2:1( reversed)• Albumin • Alkaline Phosphatase : a marker for poor bile flow• Transaminases:markers of hepatocyte integrity -ALT( SGPT: serum glutamic pyruvic (SGPT): more

specific for liver 5-45 IU

• AST( SGOT(Serum glutamic-oxaloacetic transaminase ):leakes from injured liver,heart,skeletal muscle cells or rbcs, rarely kidneys

5- 55 IU• Bilirubin :is the yellow breakdown product of normal heme

catabolism. Heme is formed from hemoglobin, a principal component of red blood cells.

• Total : • Direct (Conjugated): • Indirect (Unconjugated)

elevated

• Hemolysis• Hepatocellular disease• Biliary obstruction

• Hepatitis B Surface Antigen • LDH • Prothrombin time• Blood ammonia level• autoantibodies

Functions of the kidney

• Removal of nitrogenous waste products of metabolism

• Regulation of acid base balance• Regulation of fluid and electrolyte balance• Removal of toxins/drugs• Maintenace of BP• Production of erytropoietin

• BUN: The blood urea nitrogen (BUN) test is a measure of the amount of nitrogen in the blood in the form of urea, and a measurement of renal function. Urea is a substance secreted by the liver, and removed from the blood by the kidneys.

• Creatinine :Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass)

• Creatinine Clearance :Creatinine clearance rate (CCr) is the volume of blood plasma that is cleared of creatinine per unit time and is a useful measure for approximating the GFR.

• GFR:Glomerular filtration rate (GFR) describes the flow rate of filtered fluid through the kidney

• LDH: It catalyses the interconversion of pyruvate and

lactate with concomitant interconversion of NADH and NAD

• calcium• Phosphorus • Total Protein • Uric Acid

• Urea/creatinine ratio