Diagnostic Testing Flashcards

1
Q

Specificity

A

Ability of a test to correctly identify those who do NOT have the disease

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2
Q

Sensitivity

A

Ability of a test to diagnose those who have the disease

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3
Q

Incidence

A

Number of new cases during a specific period, in a specific population

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4
Q

Prevalence

A

Number of existing cases at a specific time, in a specific population

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5
Q

Predictive value

A

Ability of a screening test to correctly identify the disease state.

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6
Q

CBC

A

Complete Blood Count

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7
Q

WBC: Definition and Normal Range

A

White Blood Cells

5,000-10,000

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8
Q

Low WBC count

A

Leukopenia

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9
Q

High WBC count

A

Leukocytes is

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10
Q

Bashophil: Normal range and Response

A

(0.1-2%)

Inflammatory and allergy response

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11
Q

Eosinophil- Normal Range and Response

A

(1-5%)

Allergic response (asthma, parasites)

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12
Q

Monocytes- Normal Range and Response

A

(4-13%)

Fighting infection and foreign bodies

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13
Q

Neutrophils- Normal Range and Response

A

(40-70%)

Bacterial Infections

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14
Q

Lymphocytes- Normal Range and Response

A

(20-40%)

Viral Infections

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15
Q

Red Blood Cells- Normal Range

A

Erythrocytes or red blood corpuscle

4.5-5.5 million

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16
Q

Polycythemia

A

Increase in red blood cells

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17
Q

Hemoglobin- normal range for men/women

A

The protein on red blood cells that carries oxygen

Men- 14-18g/dL

Women- 12-16g/dL

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18
Q

Hematocrit- Normal range for men/women

A

Amount of red blood cells compared to the total blood volume

Men- 42-52%

Women- 37-47%

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19
Q

MCV- Normal Range

A

Mean corpuscular volume- size of the red blood cells

80-100 fl

20
Q

MCH- Normal range

A

Mean corpuscular hemoglobin- amount of hemoglobin in red blood cells

27-33

21
Q

MCHC- normal range

A

Mean corpuscular hemoglobin concentration- concentration of hemoglobin in red blood cells

33-36g/dL

22
Q

RDW- normal range

A

Red cell distribution width- variation of RBC size

11-15%

23
Q

Platelets- Normal Range

A

Used in clotting

150,000-400,000

24
Q

Thrombocytopenia

A

Low platelet count

R/O bleeding

25
Q

Thrombocytosis

A

High platelet count

R/o clotting

26
Q

MPV- normal range

A

Mean platelet volume- average size of platelets

7-10 fl

27
Q

What does a “left shift” mean?

A

Increased number of immature forms blood cells (bands = baby white cells)

There are more band cells (% bands) in a CBC with differential.

If the body is producing and mobilizing a large number of new white cells, then the body is attempting to fight off a very active infection. Normally, we only have 2-6% of our white cells as bands. If this increases, then the infection is causing the body to release bands (baby white cells) into the body before they are ready to join the fight.

28
Q

Urinalysis

A

Panel of tests with evaluates the urinate evaluate for disease

29
Q

What are the three things a urinalysis analyses?

A

Gross inspection- color, turbidity

Dipstick- specific gravity, pH, glucose, heme, protein, leukocytes, nitrites (ketones, bilirubin, urobilinogen)

Microscopy- quantify WBCs and RBCs and inspect for bacteria, crystals and casts

30
Q

Urinalysis Color

A

Hydration status

Influenced by medical conditions, medications, and ingested food

31
Q

Turbidity of Urine

A

Clear or cloudy

32
Q

Specific Gravity of Urine

A

Density of urine/Density of water

1.001-1.035

In healthy people- slightly below 1.010
1.001- more dilute. Diabetes insipidus, hydrated, ATN
1.035- dehydration, SIADH,CHF, cirrhosis, glycosuria, proteinuria, recent IV contrast
~1.010 (fixed)- advanced kidney failure, kidneys are regulating

33
Q

PH of urine

A

4.5-8.0

Low pH- acidemia

High pH- UTI, alkalemia, Distal RTA

Urine pH is highly dependent on diet, cannot be used to infer anything about the acid-base status of a patient in the absence of an ABG and metabolic panel.

34
Q

Glucose

A

Glycosuria

Hyperglycemia
Proximal tubule dysfunction

Glycosuria can lead to osmotic diuresis and dehydration

35
Q

Heme

A

Hematuria (many causes)

Rhabdomylosis

36
Q

Protein

A

Highly dependent of urine concentration

1:4 scale

Glomerular disease
Overflow proteinuria
Post-renal proteinuria (UTI)

37
Q

Leukocyte estrange and nitrites

A

Aid in diagnosis of UTI’s

L.E.- enzyme related by WBCs used as a qualitative measure of WBCs in the urinary tract. (Inflammation marker)

Nitrites- detect the presence of enterobacteriacae which convert nitrates to nitrites. (Bacteria)

38
Q

Ketones

A

Poorly controlled DM with additional trigger (infection, MI), alcoholic, starvation

Ketogenic diets

Poor sensitivity

39
Q

Urine Microscopy

A

Urine viewed under the microscope

40
Q

Microscopy- RBCs

A

or more RBCs/HPF abnormal.

UTI, renal stones, GU malignancies, recent instrumentation, coagulopathy, glomerulonephritis, sickle cell anemia, renal tuberculosis, vigorous exercise, contamination with menstrual blood.

Needs urology work up if continues to be high

41
Q

Microscopy-WBCs

A

> 5 generally abnormal

42
Q

Bacteria

A

Consistent with UTI

If L.E. And nitrates are negative consider poor collection technique

43
Q

Using UA to diagnose a UTI

A

Presence of nitrites is the most specific finding, highest positive predictive value.

Consider the presence of symptoms and a positive urine culture

44
Q

Crystals

A

Highly organized, microscopic solids usually composed of a small number of ions and molecules.

Dependent upon urine pH and concentration of ions and molecules.

Small amounts of most types are not necessarily pathologic

45
Q

Six types of crystals

A

Uric acid (tumor lysis syndrome- first round of chemo)
Calcium phosphate- (alkaline urine- Not suggestive of systemic disease)
Magnesium ammonium phosphate- (alkaline urine- UTIs by urease-producing organisms)
Calcium opal ate dihydrate-(independent of pH- not suggestive of systemic disease)
Calcium oxalate monohydrate-(independent of pH- ethylene glycol ingestion)
Cystine- (acid urine- cystinuria)

46
Q

Casts

A

Long, cylindrical structures formed in the renal tubules due to precipitation of Tamm-Horsefall much protein.

Promoted by acidic and/or concentrated urine

Described based on the elements embedded within the mucoprotein matrix

Insight into etiologies of AKI

47
Q

Types of casts

A

Acellular
-Hyaline- without other constituents- non-specific, dehydration
-Muddy brown- ATN
-Waxy- Kidney disease
-Fatty- nephrotic syndrome
-Pigment- one of several colored compounds (heme, bilirubin…)
-Granular- degeneration of a cellular gast
Cellular
-RBC- glomerulonephritis
-WBC- interstitial inflammation