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Flashcards in Laboratory Methods Deck (89):
1

What are the different types of specimens that can be collected for laboratory testing?

Blood
Body fluid
Urine
Microscopic
Stool

2

What are the different types of medical labs?

Hospital lab

Reference lab = sample gets sent outside of place it is taken

STAT lab = more expensive

Point of Care Testing = bedside

3

What is lab standardization?

Provides accurate and reproducible results

Ensures credible and comparable data across laboratories

4

What organization is in charge of lab standardization?

National Accrediting Agency for Clinical Lab Sciences (NAACLS)

5

What is considered CLinical Pathology?

Hematology
Chemistry
Immunology
Serology
Immunohematology
Microbiology
Support Services

6

What is considered Anatomic Pathology?

Histology
Cytology
Autopsy

7

Who sets the regulations for medical labs?

Center for Medicare and Medicaid Services (CMS)

These people aren’t medical workers

8

Who do laboratories work under for regulations?

Clinical Laboratory Improvement Act (CLIA)

9

What do we currently use to code and classify disease?

ICD-10

10

What are the two main purposes of HIPAA?

1) Provide continuous health insurance coverage for workers who lose or change their job

2) Reduce administrative burdens/cost of healthcare by standardizing the electronic transmission of administrative and financial transactions = this is where the privacy piece comes in

11

What is lab quality control?

Gives confidence that results are accurate and Reliable

12

What does internal lab control evaluate?

Test is working as it should

Enough sample is added

Sample is moving correctly

Electronic functions of instrument working correctly

13

What does external lab control evaluate?

Entire testing process is performed correctly

Control results are in expected ranges or values as found in manufacturer’s instructions

14

What is the reference range of a test?

Upper and lower limits generally given as range in healthy people

Normal values vary from person to person

15

What are therapeutic ranges for lab tests?

Upper and lower limits to measure medication efficacy

MIC

16

What is Diagnostic cutoff or threshold?

Presence of disease associated with value above a certain threshold

A compromise between sensitivity and specificity

It wants to minimize false negatives and false positives

17

What is Sensitivity?

Capacity to identify all individuals with disease

18

What is specificity?

Statistical term indicating effectiveness of test to correctly identify those without disease

19

What is a positive predicative value?

Likelihood that positive test identifies with disease

20

What is the negative predictive value?

Likelihood that negative test results identifies someone without disease

21

What test is an example where the threshold is selected to maximize sensitivity?

HIV screening

22

What is accuracy?

The ability of a test to actually measure what it claims to measure

Proportion of all test results (both positive and negative) that are correct

23

What is precision?

Ability of a test to reprocess the same results when reacted on the same patient or sample

24

What is the pretext probability effect?

Probability you have disease

25

What are the indications for ordering a lab test?

1) Screening
2) Establish diagnosis
3) Monitor disease
4) Monitor Therapy or medical management of disease
5) Testing related to specific event like a needle stick of sexual assault

26

What is the process for lab testing?

1) Order test
2) Patient prep for testing
3) Collect sample
4) Transport sample to lab
5) Lab receives sample
6) Lab prepares sample for testing
7) Lab reports results

27

What are preanalytical values for ordering lab studies?

1) Patient Age
2) Patient Gender
3) Body Mass
4) Preparation of the patient for testing
5) Differences in results with sample type

28

What are the standard precautions for lab studies?

Sharps Box

Gloves

Eyewear

29

What are blood studies ordered for?

1) Assess quantities of RBCs and WBCs

2) Levels of enzymes, lipids, clotting factors, and hormones

3) To establish a diagnosis = Elevate BUN and creatinine levels indicate renal failure

4) Rule out clinical problem = Normal K level rules out hyperkalemia

5) Monitor Therapy = PTT values to regulate heparin therapy

6) Establish prognosis = Declining CD4 counts reflect a poor clinical prognosis for the AIDS patient

7) Screen for disease = PSA levels to detect prostate cancer

8) Determine effective drug dosage and to prevent toxicity = peak and trough levels

30

What is the primary type of blood collected for blood studies and where is it collected from?

Venous blood

From antecubital fossa of the arm where basilic, cephalon, and median cubical superficial veins can be found

31

If you can’t use the upper extremities to obtain a blood sample, where is the next best place to obtain a venous blood sample from?

Femoral V.

32

What type of blood study is the first sample to be drawn?

Blood Cultures

33

What is serum?

Lacks clotting factor

Clotted blood sample

Clear

34

What is plasma?

Clotting factors present

Anticoagulated blood sample

Slightly more cloudy

35

What is the order of recommended blood draw?

1) Blood Cultures tubes
2) Nonadditive tubes
3) Coagulation tubes
4) Heparin tubes
5) EDTA-K3 tubes
6) Oxalate-fluoride tubes

36

What is arterial blood used to measure?

Oxygen
PH
CO2

37

What arteries are most often used for arterial blood gases?

Radial and Brachial arteries

38

What is the Allen Test?

Used to assess arterial blood flow to hand and determine potency of radial and ulnar aa.

39

When is the Allen test performed?

Prior to radial cannulation as placement may results in thrombosis

Used to reduce the ischemia to the hand

40

What does a positive Allen test reveal?

Patient does not have a dual blood supply to the hand

41

What type of body fluids can be obtained for lab study?

Sputum
CSF
Peritoneal Fluid
Pleural fluid
Semen

42

What types of swabs can be performed for lab studies?

Wound
Throat and ENT
Genital
Axilla or groin

43

What are transudate effusions caused by?

Venous Engorgement
Hypoproteinemia
Fluid Overload

44

What are exudate effusions caused by?

Inflammatory
Infectious
Neoplastic diseases

45

What does a lumbar puncture sample?

CSF

46

What does an arthrocentesis sample?

Joint fluid

47

What does a pericardiocentesis sample?

Heart

48

What does an amniocentesis sample?

uterus

49

Why is a urine sample one of the most performed bodily fluid samples?

1) Can diagnose renal or urinary tract disease

2) Can monitor renal or urinary tract disease and treatment of it

3) Can detect metabolic or systemic diseases not directly related to the kidneys

4) Identification of UTI

5) 24 hour urine collection to reflect homeostasis and disease

6) Results of blood test may be normal while urinalysis indicates the presence of metabolites

7) Serum product being tested may be affected by renal clearance

50

What does a first morning urine sample test for?

Proteinuria

51

What does a random urine sample test for?

Drug testing

52

What does a timed urine sample test for?

Postprandial glucose

53

What does a clean catch urine sample test for?

Culture

54

What are microscopic studies used for?

1) To evaluate hematologist disorders = bone marrow biopsy and blood smear

2) To detect sexually transmitted diseases

3) To evaluate dysfunctional uterine bleeding = endometrial biopsy

4) To determine liver pathological conditions = liver biopsy

5) To detect lung cancer = lung biopsy

6) To screen for cancer of the vagina, cervical, and uterus = Papanicolaou test

7) To determine the sensitivity of breast cancer to hormonal therapy = Estrogen and progesterone receptor assays

8) To detect renal disease, such as malignancy, glomerulonephritis, and transplant rejection = renal biopsy

9) To detect TB = TB culture or AFB stain

10) TO evaluate and treat infections = body fluids, wound and soft tissue culture and sensitivity

55

What are stool tests?

Used to evaluate function and integrity of bowel

Represents waste products of digested food

INcludes bile, mucus, shed epithelial cells, bacteria, and other inorganic salts

56

What is a stool test performed for?

Intestinal bleeding
Infections
INfestations
Inflammation
Malabsorption
Diarrhea

57

How do you obtain a stool sample?

Explain method in a matter of fact way

Don’t mix toilet paper or urine with specimen

If female menstruating, blood may contaminate specimen

Ask patient to defecate in designated container then place small amount in sterile collection container

58

What is endoscopy?

General term referring to inspection of internal body organs and cavities with an endoscope

Named for the organ or body area to be visualized and/or treated

59

What does an endoscopy permit?

Biopsy of suspicious tissue

Removal of polyps

Injection of variceal blood vessels

Performance of many surgical procedures

60

What does arthroscopy inspect?

Joints

61

What does Bronchoscopy inspect?

Larynx
Trachea
Bronchi
Alveoli

62

What does a colonoscopy inspect?

Rectum and COlon

63

What does a Colposcopy inspect?

Vagina and cervix

64

What does a cytoscopy inspect?

Urethra
Bladder
Ureters
Prostate

65

Why would a lab specimen be rejected?

Improperly labeled
Improper storage
Wrong tube/sample
Insufficient sample
Hemolysis
Clotted

66

What errors can occur in lab performance?

1) Pre-analytical phase errors

2) Analytical phase errors

3) Post-analytical errors

67

What are pre-analytical errors that can occur in lab performance?

Time from patient prep, through sample collection, until the sample arrive in the lab

68

When do most erros in lab test performance usually occur?

In the pre-analytical phase

69

What are analytical errors?

Time that sample is being analyzed in the lab

Errors can occur during this, but much less common now because of automation of many lab instruments

70

What is post-analytical phase errors?

Begins when result is generated and ends when the results is reported to the physician

Delay in time to enter a completed results into the lab information system

Reporting results for wrong patient

71

What is latex agglutination?

Common lab method in which latex beads are coated with antibody molecules

When mixed with patient’s specimen containing a particular antigen, agglutination with be visibly abvious

72

What does latex agglutination identify?

C-reactive protein

73

What is alternative latex agglutination?

Latex beads are coated with specific antigen

In presence of antibodies in patient’s specimen to that specific antigen on the latex particles, visible agglutination occurs

74

What tests utilize alternative latex agglutination?

Pregnancy testing
Rubella testing

75

What is hemagglutination?

Used to identify antibodies to antigens on the cell surface of RBCs

RBC agglutination would be visible

76

What is hemagglutination used for?

Blood typing for transfusions

77

What is an alternative hemagglutination method?

Different antigens can be bound to RBC surface

When added to the patient’s specimen, specific antibodies can be identified by RBC agglutination

78

What is electrophoresis?

Analytic lab method where electrical charge is applied to medium on which patient’s specimen has been placed

Migration of charged molecules in specimen can be separated in an electrical field

Proteins can then be identified based on their rate of migration

79

What is an immunoassay?

Biochemical test that measures presence or concentration of a molecule in a solution using an antibody or immunoglobulin

Relies on antibody to recogniZe and bind specific macromolecule (antigen)

80

What is the analyte in immunoassay?

Macromolecule detected by the immunoassay

81

What is the epitope in immunoassay?

Site on the molecule/antigen that the antibody binds

82

What are the different types of Immunoassays?

Enzymes (ELISA)
Radioactive Isotopes (RIA)
DNA receptors
Fluorogenic reporters
Electrochemiluminescent tags
Labeless immunoassay

83

What is a Direct ELISA?

Antibody is absorbed onto the well and sensitized the plate

Test antigen is added; if complementary, antigen binds to the antibody

Enzyme linked antibody specific for test antigen then binds to antigen, forming a double antibody sandwich

Enzyme’s substrate is added and reaction produces a visible color change that is measured spectrophotometrically

84

What is Indirect ELISA?

Antigen is absorbed onto the well and sensitizes the plate

Test antiserum is added; if antibody is complementary, it binds to the antigen

Enzyme linked anti-gamma globulin (anti-antibody) binds to bound antibody

Enzymes substrate is added and reaction produces a visible color change that is measures spectrophotometrically

85

What tests use ELISA testing?

Pregnancy testing
Monoclonal Antibody screening
Viral testing (HIV, West NIle)

86

What is direct Fluorescent antibody?

Antigen is fixed to slide and fluorescence in labeled antibody is attached to it

87

What is indirect Fluorescent antibody test?

Antigen is fixed to slide and antibody is attached to it and also fixed to slide

Fluorescein labeled antimmunoglobulin then attaches and forms an antigen-antibody complex

88

What is flow cytometry used for?

Identify cell types

Assesses cell surface markers

89

What is the goal of a western blot test?

To identify antibodies in patient serum directed at specific proteins