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Clinical Microscopy > Selected Tests (ESR, RC, OFT) > Flashcards

Selected Tests (ESR, RC, OFT) Flashcards

1
Q

rate at which red blood cells sediment in one hour (distance the RBCs settle in a given interval of time); reflects some disease states

A

Erythrocyte Sedimentation Rate

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2
Q

What usually contributes to ESR?

A

increases in plasma fibrinogen, immunoglobulins and other acute-phase proteins
changes in red cell shape or numbers

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3
Q

Why is ESR known?

A

to detect inflammation that may be caused by infection, cancer, or autoimmune disease
to follow progress of diseased state or monitor the effectiveness of treatment

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4
Q

T or F: ESR is a non-specific test

A

TRUE (presence not severity; monitors disease activity not diagnostic, no specific portion of where infection is)

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5
Q

How does ESR work?

A

anticoagulated blood is allowed to stand in a narrow vertical position undisturbed for a period of time; RBC sediments because higher density than plasma

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6
Q

unit of esr

A

mm/hr

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7
Q

this occurs in the first 10-15 minutes (1st); RBC piling up

A

stage of aggregation

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8
Q

other name of aggregation stage

A

rouleaux formation

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9
Q

What causes rouleaux formation?

A

alteration of charges on RBC surface (negatively charged) causes packing
the increased levels of fibrinogen and immunoglobulins produced during inflammation decreases negative charge of RBCs (zeta potential) to keep them apart
less negative cells sediment more rapidly than single cells

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10
Q

What comes after aggregation

A

sedimentation (occurs in the next 30-40 minutes); depends on length of tube

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11
Q

Sedimentation is the stage wherein?

A

RBCs actual falling in which sedimentation occurs at a constant rate

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12
Q

Stage of ESR which occurs in final 10 minutes

A

Packing/Stationary phase (slower rate of falling occurs due to overcrowding)

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13
Q

Plasma factors affecting esr

A 
increased esr (presence of fibrinogen, globulins, cholesterol)
decreased esr (albumin and lecithin)
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14
Q

RBC factors affecting esr

A

^weight of cell aggregate ^sedimentation rate inverseley prop to surface area
size: increased esr (macrocytic RBC, rouleaux; decreased SA to volume ratio; larger size = more rouleaux formation)
decreased esr (anisocytosis)
number: increased esr (fewer rbc ie anemia)
decreased esr (abnormal or irregular cell shape)

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15
Q

Mechanical/technical factors affecting esr

A 
increased esr (tilted esr tube, elevated room temp)
	decreased esr (short esr tubes, low room temp, delay in test performance, clotted and hemolyzed blood sample, excess anticoagulant, bubbles in tube)
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16
Q

anticoagulant/vacutainer tubes used in esr

A

EDTA (lavender:chelates the calcium molecules in blood)
heparin (green: inactivates thrombin and activated factor x)
citrate (black: calcium chelation)

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17
Q

steps involved in wintrobe method

A

→ Collect blood with anticoagulant EDTA
→ Draw blood using long stem pipette
→ Fill Wintrobe tube up to 100mm mark (should have no bubbles)
→ Place in a vertical support (slanting increases ESR)
→ Read after 1 hour by measuring length of plasma column

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18
Q

Why is wintrobe method only used for demonstration purposes?

A

short length of tubes that may lead to underestimation of ESR

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19
Q

Normal ranges in wintrobe method

A

men (0-10 mm/hr; average : 5 mm/hr)
women (0-15 mm/hr; average: 10 mm/hr)
children (1-13 mm/hr; average: 7 mm/hr)

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20
Q

Steps invovled in WESTERGREN METHOD

A

→ Load 2 mL of venous blood into a tube containing 0.5 mL of sodium citrate
→ Draw blood into a Westergren-Katz tube to the 200 mm mark
→ Allow to stand vertically for 1 hour at room temperature

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21
Q

What happens if westergren-katz tube with blood is stored longer than 2 hours at room temp/ 6 hours at 4C)?

A

increases ESR

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22
Q

Normal ranges in WESTERGREN method

A

Men (<50 yrs: 0-10 mm/hr; >50 yrs: 0-20 mm/hr)
women (<50 yrs: 0-20 mm/hr; >50 yrs: 0-30 mm/hr)
children (0-20 mm/hr)

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23
Q

(see table comparing wintrobe and westergren)

A

(see table comparing wintrobe and westergren)

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24
Q

Automated ESR analyzers

A

Sediko M-10 Automatic ESR Analyzer
DragonMed 2010-ESR Analyzer
Dispette 2-ESR Test Kit

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25
Q

instrument controlled by a microprocessor and exclusively employed for analysis of ESR

A

DragonMed 2010-ESR Analyzer (constantly and simultaneous scans 10 test tubes, results available in 30 minutes)

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26
Q

incorporates many safety features such as overflow chamber and a pierceable filling chamber cap designed to prevent spillage of blood during use and disposal

A

Dispette 2-ESR Test Kit

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27
Q

Puts 10 measuring places (slots) allow same number of independent SR tests

A

Sediko M-10 Automatic ESR Analyzer (only requirement: insert ready-made pipettes into the analyzer and subsequent processes will proceed automatically)

28
Q

T or F: Sediko analyzer is compatible with wintrobe method

A

false, westergren

29
Q

Advantages of automated ESR

A

→ Facilitate the work of the laboratory personnel

→ Results will be more precise

30
Q

Conditions associated with a highly elevated ESR (>100 mm/hr)

A
  • Giant cell arteritis
    • Waldenström macroglobulinemia
    • Polymyalgia rheumatic
    • Metastatic cancer
    • Chronic infection
    • Hyperfibrogenemia
31
Q

Conditions that may lead to a decrease in ESR

A
  • Polycythemia
    • Poikilocytosis
    • Newborn infants
    • Dehydration
    • Dengue haemorrhagic fever
    • Congestive heart failure
    • Conditions associated with hemoconcentration
32
Q

immature non-nucleated RBCs which continue to synthesize hemoglobin after loss of nucleus

A

reticulocyte (contains RNA)

33
Q

Why are reticulocytes RNA released into circulatory stystem from the bone marrow?

A

It is a usual response to some anemias or blood loss

34
Q

How large are reticulocytes?

A

20% larger by volume than mature erythrocytes

35
Q

organelles of erythrocyte

A

ribosomes, mitochondria, golgi apparatus

36
Q

estimate of red cell production and is expressed as a percentage of total RBCs

A

Reticulocyte count (normally low; reported as absolute RC or as %)

37
Q

Purposes of reticulocyte count

A

helps evaluate conditions that affect RBCs
used as follow-up to abnormal results on CBC, RBC Count, hemoglobin, or hematocrit, in order to help determine the cause
to determine if the bone marrow is functioning properly and responding adequately to the body’s needs for RBCs
help detect and distinguish between diff types of anemia
monitor response to treatments (ie IDA)
monitor bone marrow function following treatments ie chemo
monitor function following a bone marrow transplant

38
Q

What does RC measure?

A

effective erythropoiesis (RC = number of cells being delivered by marrow to blood each day)

39
Q

T or F:RNA of reticulocyte lingers longer than a day after its entry into blood

A

FALSE

40
Q

Types of reticulocyte count

A 
absolute RC
	Corrected RC
	Reticulocyte production index
	immature reticulocyte fraction
	reticulocyte specific hemoglobin content
41
Q

least mature fraction of reticulocytes which produces more RNA content and fluoresce more strongly

A

immature reticulocyte fraction (helps classify cause of anemia, assess for effective erythropoiesis, and evaluate marrow recovery)

42
Q

number of reticulocytes in a volume of blood

A

absolute RC [(no.of reticulocytes / 1000 RBcs) X 100]

43
Q

Factor that is adjusted for both the degree of anemia and maturation time of reticulocytes

A

Reticulocyte production index [corrected reticulocyte percentage/maturation time in peripheral blood (in days)]

44
Q

directly correlates with the functional availability of iron in the bone marrow (strongest predictor of IDA in children)

A

reticulocyte specific hemoglobin content

45
Q

two equivalent parameters which capture amount of hemoglobin available to reticulocytes within prev 3-4 edays in RSHC

A

mean reticulocyte hemoglobin content

reticulocyte hemoglobin equivalent

46
Q

Corrected RCs are for?

A

correction of cases in anemia because it does not consider premature release of reticulocytes in circulating blood
Corrected RC = [%Reticuloyctes (actual hematocrit/normal hematocrit)]

47
Q

What does a low ARC and low IRF indicate?

A

severe plastic anemia or renal failure

48
Q

What signifies repopulating marrow?

A

reticulocytopenia and high RF

49
Q

This indicates acute hemolysis or blood loss

A

Reticulocytosis + High IRF

50
Q

Automated reticulocyte machines use

A

fluoroscent dyes, acridine orange or thioflavin, which bind to RNA

51
Q

immunostaining in RC uses

A

Anti-CD71 (transferrin receptor) antibody

52
Q

Manual RC uses

A

methylene blue or brilliant cresyl blue which ppt RNA as dye-ribonucleoprotein complex, seen as dark blue network or as granules
supravital stain which stain living cells

53
Q

Appearance of RC in Manual staining is affected by:

A

§ Dye concentration
§ Drying method
§ pH of the stain used
§ Age of the sample

54
Q

Normal values in RC

A

adults: 0.5-1.5%

infants: 3-6%

55
Q

an increased reticulocyte count indicates?

A
  • Post-bleeding (Trauma, gastrointestinal bleeding, menorrhagia)
    • Post-hemolysis (hemolytic anemia, hemolytic disease of newborn)
    • Response to therapy (iron supp., vit b12 or folic acid supp., erythropoietin supp., bone marrow recovery ff chemo or bm transplantation)
56
Q

A decreased reticulocyte count indicates

A

• Vit. B12, folic acid, and iron deficiency
• Decreased erythropoietin level
• Aplastic anemia or bone marrow failure syndromes
• Post-radiation therapy
• Bone marrow replacement
→ Benign: metabolic storage diseases, infection, sarcoidosis
→ Malignant processes: leukemia, involvement by lymphomas or metastatic tumors

57
Q

It is used to measure RBC resistance to hemolysis while being exposed to varyling levels of dilution of a saline solution

A

osmotic fragility tests (stability of RBC in hypotonic solns)

58
Q

T or F: the sooner the hemolysis occurs, the lesser the osmotic fragility

A

false the greater the OF

59
Q

Osmotic Fragility Test is used to detect what

A

thalassemia and hereditary spherocytosis (int by Silvestroni and Bianco 1940s)
*NOT REALLY USED ANYMORE due to faster and simpler methods but still used in resource limited countries

60
Q

Principle of OFT

A

law of osmosis (Water molecules move from a higher concentration to lesser concentration through a semipermeable membrane

61
Q

concentration of NaCL in isotonic/physiological soln

A

0.9% NaCl

62
Q

T or F: RBC burst in hypertonic solns and shrink/crenate in hypotonic

A

False, burst in hypo (<0.9% NaCl), shrink in hyper (>0.9)

*hypo: hb exit from cells

63
Q

factors which affect OFT

A

• Functional state of the RBC cell membrane
→ Aged erythrocytes will be hemolyzed easily
→ Healthy cell membrane will be less fragile (reticulocytes, polycythemia, splenectomy)
• Surface-to-volume ratio
→ Increased surface area to volume ratio (low OFT due to higher resistance to hemolysis)
*more fluid is capable of absorbing before rupturing
*Examples: Thalassemia, sickle cell anemia and IDA, liver disease and any condition assoc with presence of target cells
→ Decreased surface area to volume ratio (high OFT due to decreased resistance to hemolysis)
*cells lyse at higher salt concentration
*examples: hemolytic anemia (RBCs destroyed faster), hereditary spherocytosis (genetic d in RBC membrane and decreased s to v ratio = more fragile in less hypo)

64
Q

What caused the decreased use of OFT?

A

availability of electronic counters for MCV and MCH measurement

65
Q

most used variation of OFT

A

Naked Eye Single Tube Red Cell OFT (NESTROFT) *see trans for process

66
Q

normal range for OFT

A

→ Hemolysis onset at: 0.45-0.5 % NaCl
→ Hemolysis complete at: 0.3-0.33 % NaCl
• No true consensus among laboratories in terms of a reference range of values for the osmotic fragility of erythrocyte
• Incubation of erythrocytes at 37°C for 24 hours increases the test’s sensitivity

67
Q

see sample oft ref ranges`

A

see sample oft ref ranges`

Clinical Microscopy (10 decks)

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