Principles of Laboratory Medicine Flashcards

1
Q

Lab tests consume about ___% of annual health care costs in the U.S.

A

2.3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

More than ___% of the objective data in a patient’s medical record comes from the clinical laboratory.

A

70

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is laboratory medicine?

A

The medical discipline that specializes in the performance, reporting, and interpretation of clinical laboratory tests in the provision of high quality patient care.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Who is on the laboratory medicine team?

A
  1. Pathologists
  2. Doctoral-level lab scientists
  3. Technologists
  4. Technicians
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

True or false - the specific types of clinical laboratories in health care institutions varies greatly from one place to another.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a reference lab?

A

Provide testing services for patients and healthcare providers; labs are generally specialized tests ordered infrequently or that require specialized equipment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is point of care testing?

A

Lab testing performed on simpler devices at the point of care and often by non-lab personnel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the key objective of POCT?

A

Producing a result more quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are some examples of POCT?

A

Urine HCG, glucose testing, INR, troponin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 major roles of lab tests in patient care?

A
  1. Diagnosis of disease
  2. Monitoring of disease, therapies, and interventions
  3. Screening for disease
  4. Research
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

True or false - lab tests should be ordered based on clinical questions.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the negative effects of unnecessary lab tests?

A
  1. Increased cost of healthcare
  2. Contribute to development of iatrogenic anemia
  3. Unnecessary work-up if there are errors in the diagnostic testing process
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the process of lab testing.

A
  1. Clinical develops a clinical question.
  2. Specific lab test is selected
  3. Test is ordered
  4. Specimen is collected
  5. Sample is prepared for analysis
  6. Sample is analyzed
  7. Result is verified
  8. Result is reported
  9. Test result is interpreted in the context of a clinical scenario
  10. Action is taken
  11. Patient care is affected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the 3 phases of diagnostic testing?

A
  1. Pre-analytic
  2. Analytic
  3. Post-analytic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the steps of the pre-analytic phase?

A
  1. Clinical develops a clinical question.
  2. Specific lab test is selected
  3. Test is ordered
  4. Specimen is collected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the steps of the analytic phase?

A
  1. Sample is prepared for analysis
  2. Sample is analyzed
  3. Result is verified
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the steps of the post-analytic phase?

A
  1. Result is reported
  2. Test result is interpreted in the context of a clinical scenario
  3. Action is taken
  4. Patient care is affected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the steps involved in preparation of the patient and collection of a specimen?

A
  1. Obtaining appropriate clinical history
  2. Ordering the right test
  3. Proper timing and collection of lab specimens
  4. Correct patient ID
  5. Correct specimen labeling
  6. Use of appropriate sample collection containers
  7. Proper handling and transportation of specimen
  8. Proper accessioning of specimens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the effects of misuse of clinical testing/order wrong/inappropriate tests?

A
  1. Delayed decisions
  2. Prolonged hospital stays
  3. Missed or delayed diagnoses
  4. Increased cost
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Appropriate ordering and interpretation of lab tests must incorporate the ___.

A

Clinical scenario

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

65-75% of all errors in the testing process are from the ___ phase.

A

Pre-analytical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

True or false - time of day, month, or year may affect lab test results.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are some examples of tests that must be collected at specific times or days?

A
  1. Blood counts/electrolytes (minimal diurnal variation)
  2. Hormonal level measurements (day/month)
  3. Therapeutic drug monitoring is often linked with timing of drug administration
24
Q

How do cortisol levels fluctuate throughout the day?

A

Peaks in the early morning, lowest in the late evening around bedtime

25
Q

How does cortisol vary in patients with Cushing syndrome?

A

Elevated late night salivary and serum cortisol values

26
Q

What are other biologic variables that may affect test results?

A
  1. Age
  2. Gender
  3. Race
  4. Exercise
  5. Diet
  6. Posture
  7. Genetic predisposition
27
Q

When should triglyceride level be obtained and why?

A

In the fasting state, as levels increase with eating; postprandial increase is due to presence of chylomicrons, typically 3-6 hours following a meal

28
Q

Correct ___ must be used for specimens to ensure the ordered test is performed on the specimen under proper conditions.

A

Collection tubes

29
Q

What is a common reason for specimen rejection?

A

Wrong tube type

30
Q

Different tube types contain different ___.

A

Additives

31
Q

Red cap test tubes have which additives, mode of action, and are used for which tests?

A

Additive: none

MoA: blood clots and serum is separated by centrifugation

Tests: chemistires, immunology, serology

32
Q

Lavender cap test tubes have which additives, mode of action, and are used for which tests?

A

Additive: EDTA

MoA: anticoagulant, removes Ca2+

Tests: CBC, blood bank crossmatch

33
Q

Light blue cap test tubes have which additives, mode of action, and are used for which tests?

A

Additive: 3.2% sodium citrate

MoA: anticoagulant, removes Ca2+ (preserves labile pro-coagulants)

Tests: PT, PTT, D-Dimer

34
Q

Light green cap test tubes have which additives, mode of action, and are used for which tests?

A

Additive: plasma separating tube with lithium heparin

MoA: heparin anticoagulates, plasma is separated from PST gel at body of tube

Tests: most chemistries

35
Q

Gold cap test tubes have which additives, mode of action, and are used for which tests?

A

Additive: none

MoA: Serum separator tube (SST) contains a gel at the bottom to separate blood from serum on centrifugation

Tests: Chemistries, immunology, serology

36
Q

In addition to wrong tube type, what are other reasons specimens are rejected?

A
  1. Mislabeled or unlabeled
  2. Clotted specimen
  3. QNS (quantity not sufficient)
37
Q

Why is a mislabeled/unlabeled specimen a problem?

A

Patient identity error can lead to reporting of the wrong test result for a patient

38
Q

How does a clotted specimen develop?

A

Drawing blood into a syringe and then injecting it into the tube, Overfilling a test tube that has an anti-coagulant

39
Q

How does QNS occur?

A

Stopping the blood draw before filling the tube completely

40
Q

Which phase has the least error in lab testing?

A

Analytical

41
Q

Current methods and equipment used to generate test results have a high degree of what two things?

A
  1. Accuracy

2. Precision

42
Q

What is accuracy?

A

Correctness - how closely the measurement approaches the true value of the analyte

43
Q

What is precision?

A

Reproducibility - how closely together are results from measurements of the same substance in the same sample

44
Q

Why is a precise, inaccurate lab test still accurate?

A

Trends can indicate issues

45
Q

Many lab tests are performed on ___ instruments.

A

Automated

46
Q

In addition to advances in technology, why are lab tests trending toward automation?

A

Shortage of allied healthcare personnel entering the field of lab medicine

47
Q

Despite advances in automated lab techniques, some tests are still performed ___.

A

Manually

48
Q

Once an accurate test result is obtained, the lab must do what?

A

Report the result in a timely manner by using an electronic process allowing for acceptable results to be transmitted via an interface between analyzer and the lab information system (LIS) and then another interface between the LIS and EMR

OR

Transcribing accurately the results to a paper or written medical recrod

49
Q

What are critical results of tests?

A

Results that fall significantly outside the normal range, may indicate a life threatening situation, and may require immediate clinical action

50
Q

What are the current regulations regarding a critical result?

A

Require the person receiving the report to be asked to read back the results to the lab staff member to ensure correct information was communicated; this must be documented in the medical record

51
Q

If a test results from a normal healthy patient, how are normal results determined?

A

Gaussian distribution - central 95% is the normal range (mean +/- 2 STD)

52
Q

___% of normal healthy patients may fall outside the normal cutoff values.

A

5

53
Q

___ is the ability of a test to detect disease.

A

Sensitivity (proportion of persons with disease in whom the test is positive) - rule out

54
Q

___ is the ability of a test to detect the absence of disease.

A

Specificity (proportion of persons without disease in whom the test is negative) - rule in

55
Q

What determines what level of result is considered normal/abnormal?

A

Where the lab places the threshold or cut-off on a normal or reference range