1. BLOOD CHEMISTRY AND SEROLOGY
CHAPTER 19
BLOOD CHEMISTRY AND SEROLOGY

2. PRETEST
True or False
Most of the cholesterol found in the blood comes from the intake of dietary cholesterol.
The primary use of the cholesterol test is to screen for the presence of coronary heart disease.
LDL picks up cholesterol from ingested fats and the liver and carries it to the cells.
The function of glucose in the body is to build and repair tissue.
Insulin is required for normal utilization of glucose in the body.

3. PRETEST, CONT. True or False
An abnormally low level of glucose in the body is known as hypoglycemia.
The hemoglobin A1C test measures the average amount of blood glucose over a 3-month period.
An antibody is a substance that is capable of combining with an antigen.
Mononucleosis is transmitted through coughing and sneezing.
Blood antigens (A, B, Rh) are located on the surface of red blood cells.

4. Content Outline Introduction to Blood Chemistry and Serology
Automated blood analyzers: designed for use in medical office
Perform blood chemistry tests in a short period of time
Operating manual includes:
Operation
Test parameters
Care and maintenance

5. Blood Chemistry Chemicals are dissolved in liquid part of blood
Quantitative measurement of chemical substances in blood
Quantitative test: indicates the exact amount of a substance that is present
Most blood chemistry tests require a serum specimen for the analysis.

6. Blood Chemistry, cont.
Serum specimen usually required for blood chemistry tests
Type of test ordered: depends on clinical diagnosis

7. Automated Blood Chemistry Analyzers
Reflectance photometer: measures light intensity to determine amount of substance present
Provides a quantitative measurement of chemical substances or analytes present
Examples of blood chemistry analyzers
ATAC laboratory system
Reflotron Analyzer 7

8. Automated Blood Chemistry Analyzers, cont.
Operating manual explains how to:
Collect and handle specimen
Perform quality control procedures
Test specimen
(Personnel available for on-site training)
What are quality control procedures? 8

9. Quality Control
Quality control: consists of methods and means to ensure that test results are reliable and valid
Calibration of the analyzer
Running controls
Calibration: the use of a standard to check precision of the blood chemistry analyzer
If analyzer not properly calibrated: unable to produce accurate results 9

10. Quality Control, cont.
Control: consists of a sample with a known value
Processed in same way as patient specimen
Results should fall within a specified range:
Indicated on reference sheet that comes with control
When running controls, the MA must document the results. 10

11. Quality Control, cont. Types of controls:
Normal control: results fall within normal range
Abnormal control: results fall outside of normal range
Low abnormal: below normal range
High abnormal: above normal range 11

12. Quality Control, cont.
d. If control does not fall within specified range may be caused by:
Problems or errors with analyzer
Problem with technique used to perform test
Problem with chemical reagents
Consult operating manual
The MA can also get assistance from a technical support person from the manufacturer. 12

13. Quality Control, cont. CLIA requirement: for moderate complexity tests
Calibration: at least every 6 months
Two levels of controls: daily
Example: Running a normal and high control
When problems or errors are identified:
Must document action to correct them
Medical office running CLIA-waived tests
Required to follow manufacturer’s instructions
- Include quality control procedures that must be performed
What does CLIA stand for? 13

14. Cholesterol White, waxy, fatlike substance (lipid)
Essential for normal functioning of body
Important component of cell membranes
Used in production of:
Hormones
Bile 14

15. Cholesterol, cont. Cholesterol in the blood:
Most manufactured by liver
Portion comes from individual's diet: dietary cholesterol
Found only in animal products (organ meats, egg yolks, dairy products)
What patient teaching points would the MA relay to the patient about cholesterol? 15

16. Cholesterol, cont. Cholesterol level determined by: Genetic makeup
Amount of dietary cholesterol and saturated fat consumed
What do we mean by “genetic makeup”? 16

17. Cholesterol, cont.
High cholesterol: excessive amount of cholesterol in blood
May cause atherosclerosis
Atherosclerosis: buildup of fatty deposits (plaque) on the walls of the arteries
As progresses: arteries become more occluded
Can lead to heart attack or stroke
Are there medications for high cholesterol? 17

18. Cholesterol, cont.
High blood cholesterol: risk factor for coronary heart disease (CHD)
Efforts should be made to lower cholesterol level 18

19. HDL and LDL Cholesterol
Cholesterol transported in blood as a complex molecule known as a lipoprotein
Lipoprotein: A complex molecule consisting of protein and a lipid fraction such as cholesterol
Lipoproteins function in transporting lipids in the blood 19

20. HDL and LDL Cholesterol, cont.
Two types of lipoproteins:
LDL: low-density lipoprotein
HDL: high-density lipoprotein
Which type of lipoproteins do we want to lower? 20

21. HDL and LDL Cholesterol, cont.
Picks up cholesterol from ingested fats and the liver
Delivers it to blood vessels and muscles where it is deposited in cells 21

22. HDL and LDL Cholesterol, cont.
Often referred to as "bad cholesterol"
Excess causes plaque to build up on the arterial walls (atherosclerosis)
Risk factor for CHD
Even though LDL is considered “bad cholesterol,” does a person still need it? 22

23. HDL and LDL Cholesterol, cont.
Removes excess cholesterol from cells
Carries it to liver to be excreted
Protective and beneficial to the body 23

24. HDL and LDL Cholesterol, cont.
Often called "good cholesterol"
High HDL cholesterol level: reduces risk of CHD
Below 40 mg/dL: risk factor for CHD
Can a person have too much HDL? 24

25. Cholesterol Testing Adults over age 20: Initial testing includes:
Should have a cholesterol test every 5 years
Initial testing includes:
Total cholesterol determination
Combined measurement of LDL and HDL cholesterol
What specimen would the MA collect for cholesterol testing? 25

26. Cholesterol Testing, cont.
Most physicians also order HDL determination
Measures only HDL cholesterol in the blood
Elevated results: usually require confirmation through further testing
Before diagnosis of high blood cholesterol can be made
What is the medical term for high cholesterol? 26

27. Interpretation of Results
Total cholesterol
Desirable: Below 200 mg/dL
Borderline high: 200 to 239 mg/dL
High: 240 mg/dL or higher 27

28. Interpretation of Results, cont.
High category: increased risk for CHD
Borderline high category: at increased risk if other risk factors present
Example: overweight, smoker
What instructions might you give a patient who is overweight and has high cholesterol? 28

29. Interpretation of Results, cont.
HDL Cholesterol
Optimal: 60 mg/dL or above
Desirable: 45 to 59 mg/dL
Borderline low: 40 to 45 mg/dL
Increased risk for CHD: Below 40 mg/dL 29

30. Patient Preparation Total cholesterol and HDL cholesterol:
Fasting not usually required
What does it mean when we ask a patient to fast for a test? 30

31. Patient Preparation, cont
If total cholesterol level is 200 mg/dL or higher: lipid profile usually ordered
Lipid profile includes:
Total cholesterol
HDL cholesterol
LDL cholesterol
Triglycerides
Some physicians prefer the patient to be in a fasting state for cholesterol determinations.
This test may also be used as a secondary aid in the study of thyroid and liver function. 31

32. Patient Preparation, cont.
Triglycerides affected by food consumption
Patient must fast
For at least 12 hours before test
Fasting: Abstaining from food or fluids (except water) for a specified amount of time before the collection of a specimen
What are triglycerides? 32

33. Patient Preparation, cont.
Interpretation of Test Results
Triglycerides
Normal: Below 150 mg/dL
Borderline high: 150 to 199 mg/dL
High: 200 to 499 mg/dL
Very high: 500 mg/dL or higher
Increased risk for CHD: Over 150 mg/dL 33

34. Patient Preparation, cont.
LDL Cholesterol
Optimal: Below 100 mg/dL
Near optimal: 100 to 129 mg/dL
Borderline high: 130 to 159 mg/dL
High: 160 to 189 mg/dL
Very high: 190 mg/dL or higher 34

35. What Would You Do? What Would You Not Do?

36. What Would You Do? What Would You Not Do?

37. Blood Urea Nitrogen Blood urea nitrogen (BUN): kidney function test
Urea: end product of protein metabolism
Normally present in blood
Kidney disease: may cause abnormal increase in BUN
What are some symptoms of kidney disease? 37

38. Blood Glucose Glucose: end product of carbohydrate metabolism
Function of glucose: chief source of energy for body
Energy needed to:
Carry out normal body functioning
Maintain body temperature
The body maintains a constant glucose level to ensure a continuous source of energy.
Why does the body need an energy source? 38

39. Blood Glucose, cont.
Glucose can be stored as glycogen for later use in:
Muscle tissue
Liver tissue glycogen in muscle and liver tissue for later use
When no more tissue space available to store glycogen:
Glucose is converted to fat and stored as adipose tissue 39

40. Blood Glucose, cont. Insulin
Hormone secreted by beta cells of pancreas
Required for normal utilization of glucose
Enables glucose to enter cells and be converted to energy
Also needed for proper storage of glycogen in liver and muscle cells
What disease requires insulin injections for the patients who have it? 40

41. Blood Glucose, cont. Blood Glucose Testing
Glucose measurement used to detect:
Diabetes mellitus
Hypoglycemia
Liver and adrenocortical dysfunction 41

42. Blood Glucose, cont. Testing methods Fasting blood sugar (FBS)
2-hour postprandial glucose test (PPBS)
Glucose tolerance test (GTT)
What does “postprandial” mean? 42

43. Fasting Blood Sugar FBS: patient must be fasting
No food or fluid (except water) for 12 hours before test
If a patient needs to be fasting, for when should the MA schedule the test procedure? 43

44. Fasting Blood Sugar, cont.
Medications that may affect test:
Oral contraceptives
Salicylates
Diuretics
Steroids
What is a salicylate? 44

45. Fasting Blood Sugar, cont.
Physician may restrict medications before testing
Test should be scheduled in the morning
Minimizes patient inconvenience due to fasting
FBS normal range: 70 to 110 mg/dL 45

46. Fasting Blood Sugar, cont.
Purpose of FBS
Evaluate progress of diabetic patients
Regulate treatment of diabetic patients
Routine screening procedure to detect diabetes
If a patient taking insulin has a high reading, what might the physician do to the treatment regimen? 46

47. Fasting Blood Sugar, cont.
FBS above 120 mg/dL: dividing point between normal and hyperglycemic values
Indicative of diabetes mellitus
Elevated FBS: further testing required
(e.g., GTT) 47

48. Two-Hour Postprandial Blood Sugar
Purpose
Screen for presence of diabetes
Monitor effects of insulin dosage in diagnosed diabetes 48

49. Two-Hour Postprandial Blood Sugar, cont.
Fasting required: beginning at midnight until breakfast
Breakfast: Patient consumes a prescribed meal containing 100 grams of carbohydrates
Alternative: drink 100 grams of glucose solution
Blood specimen collected 2 hours after consumption
Nondiabetic patient: glucose returns to normal within 1½ to 2 hours
The MA should give the patient written instructions about the test. Why is this important? 49

50. Two-Hour Postprandial Blood Sugar, cont.
Diabetic patient: does not return to fasting level
140 g/dL or higher: suggestive of diabetes
Warrants further testing 50

51. Glucose Tolerance Test (GTT)
Provides more detailed information on glucose utilization
Assesses insulin response to glucose load
Used to diagnose:
Diabetes mellitus
Hypoglycemia
Liver and adrenocortical dysfunction
What is hypoglycemia? 51

52. Glucose Tolerance Test (GTT), cont.
Testing Requirements
High carbohydrate diet for 3 days before test (150 grams)
Fasting
What can the MA do to make it easy for the patient to know which foods to consume? (diet sheet) 52

53. Glucose Tolerance Test (GTT), cont.
Testing procedure
FBS performed and urine is tested for glucose
If FBS indicates hyperglycemia: notify physician
Hyperglycemia contraindicates administering the glucose solution
After FBS: patient drinks measured amount of glucose (100 grams)
Why would you not want to give a patient the glucose solution if the FBS is high? 53

54. Glucose Tolerance Test (GTT), cont.
Blood and urine specimens collected at intervals: 30, 60, 120, and 180 minutes
Label blood and urine specimens with exact time of collection 54

55. Glucose Tolerance Test (GTT), cont.
Restrictions during test
No eating or drinking except water: affects glucose level
Encourage water: easier to produce urine specimen
No smoking: stimulant that increases blood glucose level
Remain at test site: so patient is present for specimen collection
Minimize activity: activity uses glucose
Affects test results
It is important to let the patient know how long the procedure will take. Why should the MA let the patient know this? 55

56. Glucose Tolerance Test (GTT), cont.
Side Effects
Patient may exhibit normal side effects during the test
Weakness
Feeling of faintness
Perspiration
Reassure patient that it is only temporary
Explain why these symptoms may occur. 56

57. Glucose Tolerance Test (GTT), cont.
Serious symptoms: immediately report to physician
Indicate severe hypoglycemia
Headache
Pale
Cold and clammy skin
Irrational speech or behavior
Profuse perspiration
Fainting
Why would a patient exhibit symptoms of hypoglycemia? 57

58. Glucose Tolerance Test (GTT), cont.
Interpretation of Results
Nondiabetic patient after ingestion of glucose solution
Glucose absorbed into bloodstream
Rises to a peak level: between 160 and 180 mg/dL
Approximately 30 to 60 minutes after consumption of glucose solution 58

59. Glucose Tolerance Test (GTT), cont.
Pancreas secretes insulin to compensate for rise
Blood glucose returns to fasting level within 2 to 3 hours
Urine is negative for glucose 59

60. Glucose Tolerance Test (GTT), cont.
Diabetic patient after ingestion of glucose solution
Blood glucose level peaks at a much higher level
Glucose present in urine
Blood glucose levels above normal throughout test
Due to lack of insulin 60

61. Glucose Tolerance Test (GTT), cont.
Hypoglycemia
Blood glucose is abnormally low
During GTT patients exhibits low level
Beginning at 2-hour interval
Continues up to 4 to 5 hours 61

62. Glucose Tolerance Test (GTT), cont.
Hypoglycemia results from:
Glucose removed from blood at an excessive rate
Decreased secretion of glucose into blood 62

63. Glucose Tolerance Test (GTT), cont.
Hypogylcemia can be caused by:
Overdose of insulin
Addison's disease
Bacterial sepsis
Pancreatic cancer
Hepatic necrosis
Hypothyroidism
What is Addison’s disease? 63

64. Glucose Tolerance Test (GTT), cont.
GTT not required if:
FBS is above 140 mg/dL
2-hour PPBS is above 180 mg/dL
Results greater than these amounts: qualify for diabetes diagnosis 64

65. What Would You Do? What Would You Not Do?

66. What Would You Do? What Would You Not Do?

67. Tests for Management of Diabetes
Important for diabetic patients to manage their condition
Best accomplished: keeping blood glucose levels close to normal
Patient experiences fewer symptoms
Delays or prevents long-term complications
Leads to a longer life
How do diabetic patients monitor their glucose levels at home? 67

68. Tests for Management of Diabetes, cont.
Types of tests
Self-monitoring of blood glucose
Performed by patient at home
Measures day-day fluctuations in blood glucose level 68

69. Tests for Management of Diabetes, cont.
Hemoglobin A1C test
Ordered by physician
Provides overall picture of blood glucose level over a period of time 69

70. Self-Monitoring of Blood Glucose (SMBG)
Diabetic patients: usually cannot tell by the way they feel
Whether blood glucose is within normal range
Only way to know for sure: SMBG
Provides patient with feedback for maintaining normal blood glucose level
Assists in anticipating and treating fluctuations in blood glucose caused by:
What are some possible long-term complications of diabetes that monitoring of blood glucose levels may help avoid? (retinopathy, peripheral vascular disease) 70

71. Self-Monitoring of Blood Glucose (SMBG), cont.
Assists in anticipating and treating fluctuations in blood glucose caused by:
Food
Exercise
Stress
Infection 71

72. Self-Monitoring of Blood Glucose (SMBG), cont.
Insulin-dependent diabetic patients:
Must monitor glucose at home for effective management
Based on results: decisions can be made regarding insulin and dietary adjustments
To maintain normal blood glucose levels
Avoids extremes of hypoglycemia and hyperglycemia
What foods should a diabetic patient avoid? 72

73. Self-Monitoring of Blood Glucose (SMBG), cont.
Reduces symptoms of the disease
Helps delay or prevent long-term complications
Examples: Retinopathy, peripheral vascular disease
Describe retinopathy. 73

74. Self-Monitoring of Blood Glucose (SMBG), cont.
Frequency of Testing
Depends on:
Severity of the diabetes
Diet
Presence of special conditions (e.g., pregnancy)
Activity level
The FBS test result (obtained in the morning) is the best overall indicator of control. 74

75. Self-Monitoring of Blood Glucose (SMBG), cont.
Insulin-dependent diabetic patient:
Ideally should monitor four times a day
In the morning: after an 8-hour fast (best overall indicator of control)
Before lunch
Before dinner
Bedtime
Before lunch, dinner, and at bedtime: provide guidance for adjusting insulin dosage, diet, and exercise
The MA should instruct the patient to keep a diary of glucose levels. 75

76. Self-Monitoring of Blood Glucose (SMBG), cont.
Test Results
Blood glucose levels
Measured using a glucose meter
Results displayed in mg/dL (milligrams per deciliter)
The MA may need to teach the patient how to use the monitor. 76

77. Self-Monitoring of Blood Glucose (SMBG), cont.
Diabetic patients: should keep a record of daily glucose test results
For periodic review by the physician
Assists physician in making decisions regarding diabetic management plan 77

78. Self-Monitoring of Blood Glucose (SMBG), cont.
Advantages of SMBG:
Most effective way to maintain normal blood glucose level
High blood glucose for a long period of time (above 180 mg/dL)
Causes progressive damage to body organs leading to:
Blindness
Kidney disease
Nerve damage
Circulation problems
What are some problems diabetic patients have due to circulation problems? 78

79. Self-Monitoring of Blood Glucose (SMBG), cont.
Convenience of testing
No physician order required
Can test any time of day
Can test when side effect occurs (e.g., hypoglycemia)
Treatment can be instituted immediately
The patient should carry the monitor and his or her medications with him or her at all times. Why is this important? 79

80. Self-Monitoring of Blood Glucose (SMBG), cont.
More involvement in self-management decisions
Insulin dosage, meal planning, physical activity 80

81. Self-Monitoring of Blood Glucose (SMBG), cont.
Reliable decisions can be made regarding insulin dosage
During situations that affect blood glucose level:
Illness
Emotional stress
Increased physical activity
Suspected hypoglycemia 81

82. Self-Monitoring of Blood Glucose (SMBG), cont.
Prevent or delay in long-term complications
Increases chance of staying healthy 82

83. What Would You Do? What Would You Not Do?

84. What Would You Do? What Would You Not Do?

85. Hemoglobin A1C Test (Hb A1C)
Assessment of average amount of glucose in the blood: over a 3-month period
Food consumed containing glucose
Glucose absorbed into circulation 85

86. Hemoglobin A1C Test (Hb A1C), cont.
Glucose has sticky quality
Sticks to protein making up hemoglobin (glycosylation)
Hemoglobin: found in red blood cells (RBCs)
Function: transports oxygen to tissues of body 86

87. Hemoglobin A1C Test (Hb A1C), cont.
Glycosylation: the process of glucose attaching to hgb
Occurs in all individuals
Both diabetic and normal
Forms a compound: hemoglobin A1C 87

88. Hemoglobin A1C Test (Hb A1C), cont.
Amount of glucose that attaches to hgb:
Proportional to amount of glucose in an individual's blood
Undiagnosed or poorly controlled diabetic patients
Have a higher than normal blood glucose level
More Hb A1C forms in these patients
What are some things diabetic patients do that lead to poorly controlled diabetes? 88

89. Hemoglobin A1C Test (Hb A1C), cont.
Hb A1C test: measures the percentage of Hb A1C
Attachment of glucose to hemoglobin: permanent for life of RBC (90 to 120 days)
Provides overall picture of blood glucose for the past 3 months 89

90. Hemoglobin A1C Test (Hb A1C), cont.
Interpretation of Results
Normal individuals: 4% to 6%
Diabetic individuals:
Recommendation: Less than 7%
Better chance of delaying or preventing diabetic complications
If higher than 8%: change in diabetic management plan required
What do IDDM and NIDDM mean? 90

91. Hemoglobin A1C Test (Hb A1C), cont.
Testing recommendations
When patient is first diagnosed with diabetes
Several times after management plan has been prescribed for a newly diagnosed patient
To verify blood glucose control is being achieved
HbA1c is run using what specimen? 91

92. Hemoglobin A1C Test (Hb A1C), cont.
c. For diagnosed diabetic patients: to evaluate effectiveness of mgt plan
Stable diabetic patients under good control: At least 2 times a year (every 6 months)
Patients who have difficulty maintaining control: Test ordered more frequently
d. After physician makes an adjustment to diabetic management plan
To assess effectiveness of change in treatment 92

93. Glucose Meters
Quantitatively measures blood glucose

94. Glucose Meters, cont. On-site testing Provides immediate results
Physician can make decisions regarding:
Diagnosis
Treatment
Follow-up care
The MA will perform the test using the glucose meter. 94

95. Glucose Meters, cont. Reagent Test Strips
Plastic strip with a reaction pad
Pad contains chemicals: react with glucose in blood
Why is it important not to touch the pad on the chemical strip?

96. Glucose Meters, cont.
Results displayed as a digital readout in mg/dL

97. Glucose Meters, cont.
Storage: cool, dry area at room temperature with cap tightly closed:
Chemicals on strip: sensitive to heat, light, and moisture
Causes deterioration of chemicals
Leads to inaccurate test results
Where would be a proper place to store the equipment in the medical office? 97

98. Glucose Meters, cont.
Strips that are discolored or have darkened: discard
To prevent inaccurate test results
Container includes desiccant
Absorbs moisture to promote dryness
Strips have an expiration date. Why is it important not to use if expiration date has passed? 98

99. Glucose Meters, cont. Care and Maintenance of Glucose Meter
Handle carefully
Physical jar could result in malfunction
Do not place in high humidity area (e.g., bathroom) 99

100. Glucose Meters, cont.
Do not expose to severe variations in environmental temperature
Example: Leaving in a vehicle on a hot/cold day
100

101. Glucose Meters, cont. Clean meter properly Exterior of meter:
Use a soft, clean cloth dampened with mild cleaning agent
Dry thoroughly
Do not let water run into glucose meter
Could damage internal components
Why is it important to clean the monitor?
101

102. Glucose Meters, cont. Replace battery
Screen displays alert of low battery
Directions for installation: specified in operator's manual
102

103. Glucose Meters, cont. Calibration Procedures Purpose of calibration:
Ensures the glucose meter is functioning properly
Ensures accurate and reliable test results
Programs the electronics of the glucose meter to match reactivity of strips in current use (compensates for variables in the manufacturing process of the reagent strip)
Where would you find the calibration device that matches the strips?
103

104. Calibrating the Meter
The code should match the numbers on the strips.

105. Glucose Meters, cont. Control Procedure Ensures:
Test results are reliable and valid
Errors are eliminated
Commercially available glucose control solutions
Use two of the following levels of controls
High
Low
What would you do if control levels were out of range? (See slide 107.)
105

106. Glucose Meters, cont. -Solution is sensitive to heat, light, moisture
c. Control solution
Effective for 3 months from date opened
After opening: write date on label
Can be used for (whichever comes first):
3 months from date opened
Expiration date stamped on label
Store control in cool, dry area at room temperature
-Solution is sensitive to heat, light, moisture
Why is it important to write the date on the label once opened?
106

107. Glucose Meters, cont.
d. If control results not within acceptable range:
Check expiration date of test strips and control solution
Make sure test strips were stored at room temperature
Make sure code on meter matches code on test strips
Review technique used to run control procedure
Correct any errors and run control again
If still not in acceptable range: contact manufacturer

108. Glucose Meters, cont. e. Should be performed
Daily, before using meter for first time
When new container of reagent strips is opened
If cap left off vial of strips for a length of time
If meter is dropped
If test has been repeated and result is lower or higher than expected
108

109. Serology Study of the serum of the blood
Specifically deals with the study of antigen and antibody reactions
Antigen: a substance capable of stimulating the formation of antibodies
Examples: Bacteria, viruses, bacterial toxins, allergens, blood antigens
Antibody: a substance capable of combining with an antigen
Results in an antigen-antibody reaction
109

110. Serology, cont. Use of serology tests
Assess the presence of a substance
Example: ABO blood typing
Diagnosis of disease
Example: Mononucleosis testing
Follow the course of a disease
Why would we perform the test for ABO blood typing?
110

111. Serologic Tests Hepatitis Test: detection of viral hepatitis
Five types of viral hepatitis: A, B, C, D, E
Determines specific type of hepatitis
For what type of hepatitis can we be immunized?
111

112. Serologic Tests, cont. Syphilis Test
Sexually transmitted disease caused by Treponema pallidum
Screening tests most commonly used
VDRL (Venereal Disease Research Laboratory)
RPR (Rapid Plasma Reagin)
Is there a cure for syphilis?
112

113. Serologic Tests, cont. Syphilis results reported as:
Nonreactive: negative
Weakly reactive: positive
Reactive: positive
Positive result warrants more specific testing
Is syphilis contagious?
113

114. Serologic Tests, cont. Mononucleosis (mono) Test
Detects presence of infectious mononucleosis
Rheumatoid Factor (RF)
Rheumatoid arthritis (RA): chronic inflammatory disease that affects joints
Blood of individual with RA: contains rheumatoid factor (RF)
Test detects presence of RF antibodies
Assists in diagnosis of rheumatoid arthritis
What is mononucleosis?
What are symptoms of RA?
114

115. Serologic Tests, cont. Antistreptolysin O test Detects ASO antibodies
Used to detect conditions resulting from strep infections and secondary strep infections:
Rheumatic fever
Glomerulonephritis
Bacterial endocarditis
Scarlet fever
What does it mean when we have a “secondary” strep infection?
115

116. Serologic Tests, cont. C-Reactive Protein (CRP)
CRP appears in blood: during inflammation and tissue destruction
Used to diagnose and determine progress of:
Rheumatoid arthritis
Acute rheumatic fever
Widespread malignancy
Bacterial infections
A rheumatoid factor and CRP may be run together.
116

117. Serologic Tests, cont. Cold Agglutinins
Detect presence of cold agglutinin antibodies
Cold agglutinins found in patients with:
Infectious mononucleosis
Mycoplasmal pneumonia
Chronic parasitic infections
Lymphoma
Name a chronic parasitic infection.
117

118. Serologic Tests, cont. ABO and Rh Blood Typing
Determines ABO and Rh blood type
Purpose
Prevent blood transfusion or transplant reactions
Identify problems (e.g., hemolytic disease of newborn)
118

119. Serologic Tests, cont. Rh Antibody Titer
Determines amount of Rh antibodies in the blood
Can occur in a pregnant woman
Rh-negative woman carrying Rh-positive fetus
Most frequent use of test:
Detect Rh incompatibility problem with a mother and an unborn child
The father may also need to be tested for the Rh antibody.
119

120. Rapid Mononucleosis Testing
Infectious mononucleosis: acute infectious disease caused by Epstein-Barr virus (EBV)
Most frequently affects children and young adults
Transmitted: saliva by direct oral contact
Often called "kissing disease"
Describe Epstein-Barr virus to the students.
120

121. Rapid Mononucleosis Testing, cont.
Symptoms
Mental and physical fatigue
Fever
Sore throat
Severe weakness
Headache
Swollen lymph nodes
What are some medications that may help alleviate the symptoms of mono (mononucleosis)?
121

122. Rapid Mononucleosis Testing, cont.
Rapid mononucleosis test: often performed in medical office
Assists in diagnose of infectious mononucleosis
Individuals with mononucleosis: produce heterophile antibody
Usually by sixth to tenth day of the illness
Test detects this antibody
How would you describe to the patient how you are going to obtain the specimen?
122

123. Rapid Mononucleosis Testing, cont.
A positive mononucleosis test and patient symptoms
Basis for diagnosis of infectious mononucleosis
What might be some patient teaching points for avoiding the spread of mono (mononucleosis)?
123

124. Blood Typing Blood Antigens Each individual has a blood type
Depends on antigens on the surface of RBCs
Blood antigen: A protein present on the surface of RBCs that determines a person's blood type
Inherited through genes
Programs the body to produce a particular antigen
124

125. Blood Antigens, cont.
Blood antigens: Grouped into categories known as blood group systems
ABO and Rh blood group systems:
Most likely to cause problems in:
Blood transfusions
Rh disease of newborn
Most commonly tested for in medical laboratory
125

126. Blood Antigens, cont. ABO blood group system:
Type A blood: A antigen present
Type B blood: B antigen present
Type AB blood: A and B antigens present
Type O blood: Neither A or B antigen is present
126

127. ABO Blood Antigens

128. Blood Antibodies
Blood antibody: A protein present in the plasma that is capable of combining with its corresponding blood antigen
To produce an antigen-antibody reaction
128

129. Blood Antibodies, cont.
Body never produces an antibody to combine with its own blood antigen
Example: If blood type is A: Plasma does not contain the A antibody
B antibody naturally occurs in this patient's plasma
B antibody cannot combine with A antigen
129

130. Blood Antibodies, cont.
If a blood antigen and its corresponding antigen combine:
A serious antigen-antibody reaction takes place
130

131. Blood Antibodies, cont. Antibodies present Type A blood: B antibody
Type B blood: A antibody
Type AB blood: Neither A or B antibody
Type O blood: Both A and B antibodies
131

132. The Rh Blood Group System
Discovered by Landsteiner and Weiner
While working with rhesus monkeys (1940)
Rh-positive: Have Rh antigen present on the surface of RBCs
Most of population is Rh-positive
Unlike the A and B antibodies, the Rh antibodies do not normally occur in the plasma.
132

133. The Rh Blood Group System, cont.
Rh-negative
15% of white population do not have Rh antigen
7% of black population do not have Rh antigen
133

134. Blood Antigen and Antibody Reactions
When blood antigen and its corresponding antibody unite
Results in clumping of RBCs: known as agglutination
Can be serious or fatal if occurs in the living body (in vivo)
Clumped RBCs cannot pass through small tubules of kidneys
Results in kidney failure
Eventually leads to hemolysis
Can occur if wrong blood type administered during transfusion
When would a patient receive a blood transfusion?
A person can bank his or her own blood for transfusion.
134

135. Agglutination and Blood Typing
Agglutination of RBCs: basis for ABO and Rh blood typing
Antigen-antibody reaction occurs in vitro
What does “in vitro” mean?
135

136. Agglutination and Blood Typing, cont.
To perform blood typing:
Commercially prepared antiserum used
Antiserum: a serum containing antibodies
Added to an unknown blood specimen
Example: Antiserum with A antibody added to unknown blood specimen
If A antigen present: combines with A antibody
Results in agglutination: indicates type A blood
What does agglutination look like?
136

137. Antigen Antibody Reaction

138. POSTTEST
True or False
Serum is required for most blood chemistry tests.
The buildup of plaque (due to high cholesterol) on the walls of arteries is known as thrombophlebitis.
An HDL cholesterol level greater than 50 mg/dL is a risk factor for coronary heart disease.
The triglyceride test requires that the patient not eat or drink for 12 hours before the test.
The normal range for a fasting blood sugar is 120 to 160 mg/dL.

139. POSTTEST, CONT. True or False
The glucose tolerance test is used to assist in the diagnosis of diabetes mellitus.
Before meals, it is recommended that the blood glucose level for a diabetic patient fall between 60 to 80 mg/dL.
The recommended A1C level for an individual with diabetes is 4 % to 6%.
The RPR test is a screening test for syphilis.
The varicella virus causes infectious mononucleosis