Lab Medicine Flashcards
(77 cards)
1
Q
Liver Function tests
A
- Excretory
- Synthetic
- Integrity of hepatocytes
- Tests for cholestasis
2
Q
Refer to Liver Case Scenario in Notes
A
..
3
Q
Excterory Liver Function tests
A
- Serum bilirubin.
- Urinary Bile Pigment.
- Bile acids.
4
Q
Synthetic Liver Function tests
A
- Plasma proteins.
- Prothrombin time.
5
Q
Test for integrity of hepatocytes
A
- Transaminases (ALT & AST).
6
Q
Tests for cholestasis
A
- Alkaline Phosphatase (ALP).
- Gamma Glutamyl Transferase (GGT).
7
Q
Metabolism of Hb
A
8
Q
How does Bilirubin exist in the serum?
A
- Unconjugated (indirect) bilirubin
- Conjugated (Direct) bilirubin
9
Q
Compare between unConjugated & Conjugated bilirubin in terms of:
- Normal Site
- Solubility
- Fate
A
10
Q
What is the Fate of urobilinogen?
A
- Most of it converted into stercobilin & excreted in feces (brown color).
- Part of it oxidized to urobilin & excreted in urine (yellow color).
11
Q
Def of Delta-Bilirubin
A
- Conjugated bilirubin covalently bound to albumin.
12
Q
Level of Delta-Bilirubin
A
- Normally: Absent or present in very small amount.
- Increases in: cholestasis (in parallel with other fractions).
13
Q
Clearence of Delta-Bilirubin
A
- Cleared slowly from circulation to urine so:
- When jaundice resolves the delta fraction (which is not filtered) still present & bilirubin testing may become -ve in spite of high serum level.
14
Q
Causes of increased unconjuguated bilirubin
A
15
Q
Causes of increased Conjugated bilirubin
A
16
Q
What is Gilberts Syndrome?
A
Most common cause of Unconjugated hyperblirubinemia
- Deficiency of uridinediphosphoglucuronyl transferase enzyme (UDP-GT).
- There is defect in the uptake by hepatocytes.
17
Q
What is Dubin-Johnson Syndrome?
A
- A defect in excretion of bilirubin by hepatocyte.
18
Q
Site of formation of plasma proteins
A
Most of them: in liver.
Except gamma globulins: in plasma cells.
19
Q
Level of albumin
A
- Represent: 60% of total serum protein.
- Level: 3.5 - 5.0 g/di.
20
Q
What happens to synthetic liver function tests in advanced hepatic affection?
A
21
Q
What forms blood coagulation factors?
A
- Most of coagulation factors (except factor VIII) & fibrinolytic enzymes → by the liver.
- Factor VIII → by spleen.
22
Q
What happens in patients with hepatocellular damage?
Concerning Blood coagulation factors
A
Decrease in Coagulation factors → Increase Prothrombin time [PT] (an early abnormality in this disease).
23
Q
Normal site of ALT & AST
A
Inside Hepatocytes
24
Q
What hapens to serum Levels of ALT & AST in hepatitis?
A
25
What is **Preicteric phase**?
- the period prior to appearance of jaundice
26
What happens to serum level of **ALP** in Obstructive Jaundice?
In obstructive jaundice "serum level is markedly elevated (>3 URL)"
27
What happens to serum level of **GGT** in cholestasis & Liver cirrhosis?
Serum Level: Inc. in cholestasis & liver cirrhosis (but the rise is marked in cholestasis).
28
What are other causes of elevated **GGT**?
Alcohol & barbiturates
29
30
Types of **Plasma amaylase**
- Salivary (S-isoenzyme)
- Pancreatic (P-isoenzyme): More specific & sensitive for diagnosis of acute pancreatitis.
- Total amylase activity > 10 times URL is virtually diagnostic of acute pancreatitis.
31
Definition of **Tumor Markers**
- A substance found in an increased amount in (blood - other body fluids - body tissues) that may suggest the presence of a type of cancer.
32
Method of measurment of **Tumor Markers**
- Qualitatively or quantitatively by chemical, immunological or molecular biological methods (PCR) to identify the presence of cancer.
33
Uses of **Tumor Markers**
**Screening in general population:**
- It is of limited value as it doesn't confirm diagnosis.
- May aid diagnosis in high-risk people.
**Differential diagnosis in symptomatic individuals:**
- But must be in conjunction with clinical & radiological evidence.
**Prognostic indicator of disease progression:**
- As the plasma concentration correlates with the tumor mass.
**Monitoring of response to therapy & detecting recurrence.**
34
Categories of **Tumor Markers**
- Enzymes
- Hormones
- Oncofetal Antigens
- Blood Group Antigens
- In addition to : Proteins, Hormone Receptors, Genetic markers
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Enzyme **Tumor Markers**
36
Hormonal **Tumor Markers**
37
Oncofetal antigins as **Tumor Markers**
38
Blood group antigens as **Tumor Markers**
39
What is a **Sample**?
A biological material taken from a patient for diagnostic, prognostic or therapeutic monitoring.
40
Types of samples
- Blood.
- Sweat.
- Urine & other fluids.
- Semen.
Feces.
Tissue.
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Collection site of blood samples
42
Types of blood samples
- Venous sample.
- Capillary sample.
- Arterial sample.
43
In Blood sample collection, Avoid the hand with ……
- Extensive scarring.
- Burn.
- Hematoma.
- Containing I.V. access for I.V. infusion.
- Infection.
- On the side of mastectomy.
- Edema.
44
Cleansing of venipuncture site
45
Types of urine samples
46
Outcomes of Improper sample collection
47
Specimen Quality & Markers for rejection
48
Refer to Thyroid Case Scenario in Notes
..
49
Tests to assess thyroid function
TSH (Thyroid Stimulating Hormone).
Free T3.
Free T4.
50
What are other tests to assess the function of thyroid gland?
TSI
51
Aim of **TSI Testing**
to determine the cause of the disease.
52
Lab results of **TSI**
53
Thyroid Disorders and T4,T3 & TSH levels
54
What are Variables affecting (T3- T4 - TSH) testing?
- Hospitalized patient & recovery from Iliness.
- Pediatric & neonate.
- Pregnancy.
- Drug treatment.
- Assay interference.
- Reference range.
- Follow up test selection.
55
Def of **Euthyrold sick syndrome (ESS)**
- Abnormal levels of thyroid hormones despite normal thyroid gland function.
56
Synonyms of **Euthyrold sick syndrome (ESS)**
- Sick Euthyroid Syndrome (SES).
- Non-Thyroidal tilness syndrome (NTI).
57
Etiology of **Euthyrold sick syndrome (ESS)**
Occurs in severe illness or severe physical stress Most common in intensive care patients"
58
Pathophysiology of **Euthyrold sick syndrome (ESS)**
59
Patterns of **Euthyrold sick syndrome (ESS)**
60
Clinical features of **Euthyrold sick syndrome (ESS)**
No symptoms of hypothyroidism (as It Is a temporary state).
61
TTT of **Euthyrold sick syndrome (ESS)**
Once the person recovers from the Iliness → thyrold hormone returns to normal.
62
Neonatal Thyroxine Levels at birth
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Neonatal Thyroxine Levels then
64
Examples of **Conditions causing Increase of plasma TBG**
Cases associated with Increased estrogen:
* Pregnancy.
* Oral contraceptives.
65
Effect of **Conditions causing Increase of plasma TBG**
Lead to false inc. of Total T4 & T3.
66
Reliable test in **Conditions causing Increase of plasma TBG**
Free T3 & Free T4 reliable In these cases.
67
Examples of **Conditions causing Decrease of plasma TBG**
Protein losing states
68
Effect of **Conditions causing Decrease of plasma TBG**
Cause a false dec of Total T4 & T3.
69
Reliable test in cases of **Conditions causing Decrease of plasma TBG**
Free T3 & Free T4 reliable In these cases.
70
What are Drugs that interfere with thyroid function leading to thyroid disfunction (Hypo or hyperthyroidism)?
71
Def of **Assay Interference**
- A nonspecific binding with assay reagents leading to false increase in concentration of the measured substance.
72
What is **Thyroid Assay**?
An animal anti-body against thyroid hormones used to determine their serum level.
73
Thyroid assay interference
74
Def of **reference Range**
A set of values that Includes upper & lower limits of a lab test based on a group of otherwise healthy people.
75
Is **reference Range** Age related?
yes
76
**reference Range** Must be trimester related in pregnancy
..
77
What test is used in follow up in cases of thyroid dysfunction?
