Laboratory Review Session

1. Laboratory Review Session Lucinda Hirahoka August 2005

2. Complete Blood Count • Synonyms: Blood cell profile; blood count; CBC; hemogram • Test commonly include: WBC, Hct, Hgb, differential count, RBC, WBC and RBC morphology, RBC indices, platelets estimate, platelet count, RDW, and histograms. • Critical values: Hematocrit <18% or >54%; hemoglobin: <6.0g/dl or 18.0g/dl; WBC on admission: <2500/mm3 or >30,000/mm3; platelets: <20,000/mm3 or >1’000,000/mm3. • Use: Evaluate anemia, leukemia, reaction to inflammation and infections, peripheral blood cellular characteristics, state of hydration and dehydration, polycythemia, hemolitytic disease of the newborn; manage chemotherapy decisions.

3. Case Study • 16 yr old Latino female brought by mother because she is acting tired. ROS neg, except for dietary habits (fast food) and Hx heavy menses. Menses last 7 days, menarche age 10 never had pelvic exam. Junior in high school, gets good grades but school is boring

4. Case Study • What lab test would you order to help you with the diagnosis of this patient?

5. Case Study • WBC 6.2 Iron 12 • RBC 3.38 TIBC 437 • Hgb 5.8 Ferritin 0 • Htc 20.2 anyso 2+ • MCV 60 3+ microcytosis • MCH 17.2 3+ hypochromosis • MCHC 28.8 • RDW 17.9

6. Case Study • What type of anemia does this patient have? • What are the other types of anemia?

7. Red Cell Indices • The red cell indices provide information about the size, hemoglobin concentration, and hemoglobin weight of an average RBC. The indices include mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC).

8. Mean Corpuscular HemoglobinConcentration (MCHC) • MCHC is a measure of the amount of hemoglobin present in the average red blood cell. It defines the concentration of hemoglobin in 100ml of packed red cells. It helps distinguish normally colored (normochromic) red cells from paler (hypochromic) red cells.

9. Mean Corpuscular Hemoglobin(MCH) • MCH gives the weight of hemoglobin in an average red cell.

10. Mean Corpuscular Volume(MCV) • MCV is a measure of the volume or size of the average red blood cell. The MCV is often used in the evaluation of anemia. The MCV helps to classify the type of anemia and indicates whether they are undersized (microcytic), oversized (macrocytic), or normal (normocytic)

11. Red Blood Cell Distribution Width Normally, most red blood cells are equal in size. In many types of anemia there is variability in red blood cell size. RDW is a measure of this variability. Anisocytosis is a variation in the size of the red blood cell due to unequal hemoglobin content. • Poikilocytosis is the presence in the blood of erythrocytes showing abnormal variation in shape.

12. Reticulocyte Count • Reticulocytes are nonnucleated, immature red cells that remain in the peripheral blood for 24 to 48 hours while they mature. The reticulocyte count reflects the ability of the bone marrow to produce new red blood cells and is adequately responding to the anemia

13. Serum Iron • Iron is essential to the formation and function of hemoglobin as well as many other heme and non-heme compounds. Iron appears in the plasma bound to a glycoprotein called transferrin. • Transferrin is a transporter for iron in the bloodstream

14. Total Iron Capacity • Total iron-binding capacity (TIBC) measures the amount of iron that would appear in plasma plus the amount of transferrin available in serum. Normally, transferrin is about 30% saturated. • In iron deficiency anemia, serum iron levels drop and TIBC increases.

15. Serum Ferritin • Ferritin, a major iron-storage protein found in reticuloendothelial cells, normally appears in small quatities in serum. In adults, serum ferritin levels are directly related to the amount of available iron stored in the body.

16. Case Study • So what about our case?

17. White Blood Cells • White blood cells (leukocytes) include neutrophils, monocytes, lymphocytes, eosinophils, and basophils. • An increase in any of these cells types can lead to leukocytosis.

18. Leukocytosis • Defined as a white blood cell count greater that 11,000 per mm3. It is a normal protective response to stresses such as invading microbes strenuous exercise, anesthesia, and surgery. • Leukopenia is an abnormal level of white blood cells below 5,000 per mm3, at it may be caused by radiation, shock, and certain chemotherapeutic agents.

19. Leukocytosis • The estimated life span of a white blood cell is 11 to 16 days. • The normal reaction of bone marrow to infection or inflammation leads to an increase in the number of white blood cells, predominantly polymorphonuclear (older neutrophils) leukocytes and less mature cells forms like band cells and metamyelocites which move to the site of injury or infection. The increase of less mature white blood cells is commonly referred to as a “left shift”.

20. Significance of High and Low WBC • Neutrophils • Neutrophilia is the most common type of leukocytosis. • High: Bacterial Infection, burns, stress, inflammation • Low: Radiation exposure, drug toxicity, vitamin B12 deficiency, and SLE

21. Significance of High and Low WBC • Lymphocytes • High: Viral infections (mono), some leukemias • Low: Prolonged illness, immunosuppression, and treatment with cortisol.

22. Significance of High and Low WBC • Monocytes • High: Viral or fungal infections, tuberculosis, some leukemias, other chronic diseases • Low: Bone marrow suppression, treatment with cortisol

23. Significance of High and Low WBC • Eosinophils • High: Allergic reactions, parasitic infections, autoimmune diseases • Low: Drug toxicity, stress

24. Significance of High and Low WBC • Basophils • High: Allergic reactions, leukemias, cancers, hypothyroidism, connective tissue disease • Low: Pregnancy, ovulation, stress, and hyperthyroidism

25. Sedimentation Rate • Synonyms: ESR, Westerngren • ESR is a generally nonspecific measure of inflammation and infection. It is used mainly to follow management of rheumatology patients. Important in clinical evaluation of temporal arteritis and polymyalgia rheumatica.

26. KIDNEY FUNCTION

27. Serum Creatinine • Serum creatinine is a result from catabolism of creatinine phosphate in skeletal muscle. Normally, the blood creatinine level remains steady because the rate of creatinine excretion in the urine equals its discharge from the muscle. A creatinine level of 1.5mg/dL usually is an indication of poor renal function. • Concentrations of creatinine only becomes abnormal when about half or more of the nephrons have stopped functioning in chronic progressive renal disease

28. Serum Creatinine • Causes of High creatinine includes renal diseases and insufficiency with decreased glomerular filtration (uremia or azotemia if severe); urinary tract obstruction, reduced renal blood flow including CHF, shock and dehydration; rhabdomyolysis causes high serum creatinine. • Causes of low creatinine include small stature, debilitation, decreased muscle mass, some complex cases of severe hepatic disease. In advanced liver disease low creatinine may result from decreased hepatic production of creatinine and inadequate dietary protein as well as reduced muscle mass.

29. Blood Urea Nitrogen • Test that measures the blood nitrogen that is part of the urea resulting from catabolism and deamination of amino acids. • Urea is easily filtered by the renal glomeruli and is partially reasorbed by the renal tubules. Urea nitrogen reflects the ratio between urea production and clearance. Increased BUN may be due to increased production or decrease excretion.

30. BUN • High BUN occurs in chronic glomerulonephritis, pyelonephritis, and other causes as in shock. BUN is helpful in following dyalisis patients. Moderate dehydration may increase BUN. Other causes of eleveted BUN are CHF, increased protein catabolism, ketoacidosis, hyperalimentation, it is dependent on renal flow and urinary flow rates. Corticosteroids tend to increase BUN due to increase protein catabolism • Low BUN occurs in late pregnancy, decrease protein intake and severe liver damage.

31. DIABETES

32. Glycated Hemoglobin • Synonyms: Fats hemoglobins, GHB, HBA, Hemoglobin A1c • Glycated hemoglobin is an irreversible glucose-protein bond which extends through the life of an erythrocyte. Glycated hemoglobin values are used to assess long-term glucose control in diabetes. • Normal range varies from 4% to 7%. There is no age dependence. The risk of microalbuminuria with insulin-dependent DM increases above HBA1c of 10.1%.

33. Glycated Hemoglobin • Glycated hemoglobin values are used to assess long-term glucose control in diabetes. Chronic blood loss, hemolytic anemia or other setting for decrease in RBC life span, results in a decrease in the glycated hemoglobin level. Pregnancy as well as chronic renal failure may lower levels of HBA1c

34. Ketones Bodies • Synonyms: Ketones, Nitroprusside reaction in blood • Carbohydrate deprivation and increased catabolism of fatty acids leads to increases in the ketone bodies (acetoacetase and acetone).

35. Fructosamine • Synonyms: Glycated Albumin • Normal ranges vary considerably according to method. Nondiabetics 1.5-2.7 mmol/L, diabetics > OR = 2.0 –5.0 mmol/L depending on the degree of control. • It is use to evaluate diabetic control, reflecting diabetic control over a shorter time period (2-3 weeks) than that represented by glycated hemoglobin (hemoglobin A1c) (4-8 weeks). Indicated as an index of longer term control than glucose levels, especially in diabetics subjects with abnormal hemoglobin, patients with gestational diabetes, and in type 1 diabetes in children. Fructosamine levels may be useful in screening geriatric populations. Very low albumin levels concentration (<3.0 g/dL) may result in falsely low fructosamine. • Not a good test for diagnosing or screening for DM.

36. Ketones • It helps to diagnosed ketonemia, ketoacidosis resulting from diabetes mellitus, alcoholism, stress, starvation, intestinal disorders including emesis, glycogen storage diseases (von Gierke’s), infantile organic acidemias, and other metabolic disorders.

37. Ketones • In infants and children, ketonuria can occur with febrile illnesses, toxic states with marked vomiting or diarrhea. • In adult healthy men, a fast of 18 hours or greater produces ketonemia at a level that would result in detectable ketonuria. Aging is associated with increased susceptibility to fasting-induced hyperketonemia.

38. Ketones • Ketones, Urine • Semiquatitative test to evaluate ketonuria, detect acidosis, ketoacidosis of alcoholism and diabetes mellitus, fasting, starvation, high protein diets, and isopropanol ingestion. Remains useful as a monitor in known diabetics in type I when ill and during marked hyperglycemia and in type II diabetics during acute illness. In pregnancy, the risk of ketosis is increased; all pregnant type I diabetics are advised to monitor urine for ketosis in first morning urine and when blood glucose is >150 mg/dL.

39. LIVER FUNCTION

40. Liver Profile Synonyms: Liver battery, liver panel • Liver profile most often includes total bilirubin, conjugated bilirubin, alkaline phosphatase, LD (LDH), AST (SGOT), with ALT (SGPT), GGT (GGTP). It may also include serum protein electrophoresis, prothrombin time, and hepatitis serology when indicated.

41. Alanine Aminotrasferase Synonyms: ALT; Glutamic Pyruvale Transaminase; GPT; SGPT;Transaminase ALT is a cellular enzyme. It is present in the liver, heart, and kidney. Reference range: Typical reference range 10-35 units/L. Increases of tenfold occur in some cases of hepatitis and shock.

42. ALT • Use: A liver function test, ALT is more sensitive for the detection of hepatocyte injury than for biliary obstruction. ALT is more specific for liver injury than AST (SGOT). Useful for hepatic cirrhosis, and other liver diseases.

43. Asparate Aminotransferase • Synonyms: AST; Glutamic Oxaloacetic Transaminase, Serum; GOT; L-Aspartate: 2-Oxoglutarate Aminotransferase; SGOT; Transaminase. • AST is present in the heart, liver, skeletal muscle, kidney, pancreas. When an increase of AST is from the liver, it is likely to relate to disease of the hepatocyte.

44. AST • High AST is caused by various entities like: cirrhosis, alcoholic hepatitis, viral hepatitis, cholecystitis, Reye’s syndrome, mononucleosis, trauma and other striated muscle diseases. • Very high values, >500 units/L, usually suggest hepatitis or other types of hepatocellular necrosis but can also be found with large necrotic tumors, other types of necrosis or extensive hypoxia, congestive failure, and shock. Unexplained AST elevations should first be investigated with ALT and GGT.

45. Alkaline Phosphatase (ALP) • Synonyms: ALP; Phosphatase, Alkaline • Serum alkaline phosphatase (ALP) activity normally originates from liver and bone. Other sources include intestine and placenta. ALP is excreted in bile. Serum total ALP level provides a useful but nonspecific indication of liver or bone disease. With biliary tract obstruction, the rise in ALP parallels increase in serum bilirubin. An elevated gamma glutamyl transferase would indicate that the liver is the source of the elevated ALP. • Reference range: Adult normal range is approximately 50-120 units/L.

46. Alkaline Phosphatase • Uses: Causes of high alkaline phosphatase include: nonfasting specimen, bone growth, healing fracture, acromegaly, osteogenic sarcoma, liver or bone metastases, leukemia, myelofibrosis, and rarely myeloma. Alkaline phosphatase is used as a tumor marker. • To confirm biliary abnormality, an additional useful test is GGT which is elevated in hepatobiliary disease. • Serum ALP is increased during pregnancy. Marked decline of high ALP of pregnancy is seen with placental insufficiency and imminent fetal demise.

47. Gamma Glutamyl Transferase • Synonyms: Gamma Glutamyl Transpeptidase; GGT; GGTP; Glutamyl Transpeptidase; GT; GTP. • Used in diagnosis of obstructive jaundice and alcohol abuse. • Reference range varies between laboratories.

48. GGT • GGT is a biliary enzyme that is especially useful in the diagnosis of obstructive jaundice, intra-hepatic cholestasis, and pancreatitis. GGT is more helpful than AST, SGOT and ALT to work obstruction. In obstructive disease values as high as 5-50 times the upper limit of normal are seen. In infectious hepatitis values seldom go above 5 times normal. • GGT is the test for cholestasis during or immediately following pregnancy. • GGT is a biliary excretory enzyme which is more specific for hepatic disease than is alkaline phosphatase. GGT has no origin in bone or placenta.

49. Total Bilirubin • Bilirubin: Is a normal, yellow to green pigment of bile derived from the porphyrin structure of hemoglobin. • Synonyms: Total bilirubin. • Normal value <1.0 mg/dl • Increase with biliary obstruction

50. Bilirubin, Direct • Bilirubin, Direct • Synonym: ConjugatedBilirubin, Direct bilirubin. It is formed by unconjugated bilirubin which moves from the plasma to the hepatocyte and joins to glucuronic acid to become conjugated. It becomes a water soluble substance and it can be excreted in the bile. • Normal values: 0.2-0.4 mg/dl • Elevated direct bilirubin (conjugated fraction) is evidence of liver or biliary disease. • When conjugated bilirubin is increased in serum, bilirubin should become positive in the urine.