Interpreting test results Flashcards
1
Q
What is the clinical process before a test
A
Consultation History/exam Request Report Differential diagnosis Choice of test
2
Q
What are the contents of a lab report
A
- Demographic details
- Results from lab analysis
- Reference ranges
- Comments and advice
3
Q
What is the “Normal range”
A
Defines the values of biochemical test found in healthy subjects against which patient values can be compared
4
Q
What is the +/- in the reference range
A
- 2SD/+2SD
- 5% of patients have false neagtive/positive
5
Q
Strategies to improve tests
A
- Select a more appropriate ‘normal’ population
- combination of tests
6
Q
What would be an appropriate normal population
A
- same age, gender etc
- similar presenting symptoms
- Hospitalised “normals”
7
Q
What is the 2 line, 2 range tests
A
- to differentiate between positives and false positives
- reference line adjusted in sensitive test
- Any positives past that point have specific test
8
Q
Example: Cortisol
A
- measurements only taken between 9-12 as reference ranges are narrow
- cant control what patients do after
- measuring a base line would not be reflective
9
Q
Action limits + examples
A
- When reference ranges are not useful
- Cholesterol - cut offs tell us what the risk is
- Paracetamol - No normal range only specific amounts
10
Q
Therapeutic ranges + examples
A
For dugs that are effective at low levels but toxic at higher.
- Lithium, Digoxin
11
Q
Interpretation of Biochemical values
A
- Made under appropriate conditions (fasting/not)
- Interpreted in light of the appropriate reference range
12
Q
What is the clinical significance of Protein + Glucose
A
- Forms Advanced Glycosylated Endproducts (AGE)
- Non-enzymatic process
- Rate of formation proportional to glucose conc and time
13
Q
What is HbA1c
A
- A stable glycosylated haemoglobin
- protein within haemoglobin that carries oxygen has joined with glucose in the blood
- Higher the level of HbA1c, greater risk of developing diabetes
