Automation Flashcards
1
Q
marked the first clot detection instrument
A
Koagulovis-dosimeter
2
Q
laid the foundation for PT and PTT assays.
A
Gram’s method
3
Q
Initial testing involved manual methods like the
A
tilt-tube technique
4
Q
Traditional Coagulation Testing
A
● Prothrombin Time (PT) with international ratio (INR)
● Partial thromboplastin time (PTT/APTT)
● Fibrinogen and thrombin assays
5
Q
Assay end-point detection principles
A
- Observation-Based End-Point Detection
- Feel-Based End-Point Detection
- Technological Advancements
- Modern Instrumentation
6
Q
Assay end-point detection principles
Optical and Nephelometric Devices
A
Observation-Based End-Point Detection
7
Q
Assay end-point detection principles
Utilizes “Observation” of Clot Formation
A
Observation-Based End-Point Detection
8
Q
Assay end-point detection principles
Commonly used in Traditional Coagulation Instruments
A
Observation-Based End-Point Detection
9
Q
Assay end-point detection principles
Mechanical and Viscosity Based Devices
A
Feel-Based End-Point Detection
10
Q
Assay end-point detection principles
Detects clot formation by “Feel”
A
Feel-Based End-Point Detection
11
Q
Assay end-point detection principles
Early instruments primarily relied on mechanical principles
A
Feel-Based End-Point Detection
12
Q
Assay end-point detection principles
Traditional to Photo-Optical Detection
A
Technological Advancements
13
Q
Assay end-point detection principles
Traditional to Photo-Optical Detection
A
Technological Advancements
14
Q
Assay end-point detection principles
Technological Advancements Fixed wavelength between
A
500 and 600 nm
15
Q
Assay end-point detection principles
Integration of Viscoelastic End-Point Detection for Specialty Testing
A
Technological Advancements
16
Q
Assay end-point detection principles
Integration of Multiple-End Point Mechanisms
A
Modern Instrumentation
17
Q
Assay end-point detection principles
Incorporation of Chromogenic and Immunoassay-Based Testing
A
Modern Instrumentation
18
Q
Assay end-point detection principles
Streamlining Laboratory Workflows for Routine and Specialized Testing Needs
A
Modern Instrumentation
19
Q
Measure a change in conductivity between two metal electrodes in plasma
A
Mechanical Clot End-Point Detection
20
Q
Mechanical Clot End-Point Detection
A
- BBL fibrometer
- Magnetic sensors
21
Q
Mechanical Clot End-Point Detection
first semi-automated instrument to be used routinely in the coagulation laboratory
A
BBL fibrometer
22
Q
Mechanical Clot End-Point Detection
Has one stationary and one moving electrode
A
BBL fibrometer
23
Q
BBL fibrometer principle:
A
Moving electrode: enters and leaves (breaks the current between the electrodes) the plasma at regular intervals
24
Q
When a clot forms, the fibrin strand conducts current between the electrodes even when the moving electrode exits the solution. (stops the timer
A
BBL fibrometer
25
Another method that uses magnetic sensors that monitors the movement of a steel ball within the test plasma
Magnetic sensors
26
An electromagnetic field detects the oscillation of a steel ball within the plasma-reagent solution (fibrin formation increases viscosity and slows the movement until the oscillation decreases to a predefined rate — timer stops)
Magnetic sensors
27
A steel ball is positioned in an inclined well. As the well rotates, the ball remains positioned on the incline and is only swept out as fibrin forms. The position is detected by a magnetic sensor. Timer stops as it moves away from the sensor.
Magnetic sensors
28
Detect changes in plasma optical density (OD) during the clotting process
Photo-Optical Clot End-Point Detection
29
Light of a specific wavelength passes through the sample, and its intensity (OD) is recorded by a photodetector
Photo-Optical Clot End-Point Detection
30
Photo-Optical Clot End-Point Detection OD depends on
specimen color and clarity
31
Photo-Optical Clot End-Point Detection principle
Formation of fibrin strands causes light to scatter → less light to fall on the photodetector → increase in OD
Timer stops when the OD rises to a predetermined variance from the baseline
32
Used to detect clot formation in the past and is still used today in particular instruments for whole blood clotting
Viscoelastic Clot Detection
33
Viscoelastic Clot Detection
Information can be obtained on:
○ The time of clot
○ Kinetics of whole blood clot formation
○ Clot strength
○ Fibrinolytic activity
34
Uses a synthetic small peptide substrate (three amino acids that matches the factor) conjugated to a chromophore (para–nitroaniline or pNA)
Chromogenic End-Point Detection
35
Measures the activity of a specific coagulation factor (exploits the factor’s enzymatic properties
Chromogenic End-Point Detection
36
In Chromogenic End-Point Detection, The OD of the solution is proportional to protease activity and is measured by a photodetector at
405 nm
37
Chromogenic End-Point Detection:
OD is proportional to the activity of the analyte being measured
Direct Chromogenic Assay
38
Example of Direct Chromogenic Assay
Protein C activity
39
Chromogenic End-Point Detection:
Protein or analyte being measured inhibits a target enzyme (has the activity toward the chromogenic substrate)
Indirect Chromogenic Assay
40
Chromogenic End-Point Detection:
OD is inversely proportional to the concentration or activity of the substance being measured
Indirect Chromogenic Assay
41
Example of Indirect Chromogenic Assay
anti-factor Xa assay
42
Is a modification of photo-optical end-point detection in which 90-degree or forward-angle light scatter rather than OD is measured
Nephelometric End–Point Detection
43
A light-emitting diode produces incident light at approx. 600 nm, and a photodetector detects variations in light scatter at 90 degrees (side) and 180 degrees (forward)
Nephelometric End–Point Detection
44
Formation of fibrin polymers causes side and forward-angle scatter to rise. Timer stops as it reaches a predetermined intensity
Nephelometric End–Point Detection
45
In Nephelometric End–Point Detection, Continuous readings throughout the clotting period produce a
clot curve or signature
46
Provides a quantitative assay of coagulation factors
Nephelometric End–Point Detection
47
Are based on antigen–antibody coagulation testing
Immunologic Light Absorbance End-Point Detection
48
Uses light absorbance to detect an end-point
Immunologic Light Absorbance End-Point Detection
49
Latex microparticles are coated with antibodies directed against the selected antigen, forming agglutinates that absorb light that is proportional to the antigen levels
Immunologic Light Absorbance End-Point Detection
50
Immunologic Light Absorbance End-Point Detection principle:
The increased in light absorbance is proportional to the size of the agglutinates, which in turn is proportional to the antigen level.
51
Are useful to evaluate specimens from patients who have circulating inhibitors or who are on treatment
Chromogenic end-point
52
Is isolated to the specific chemical (enzymatic) reaction in question rather than the entire coagulation cascade
Chromogenic end-point
53
More specific than clot–based assays
Chromogenic end-point
54
Not affected by icterus or lipemia
Mechanical clot end–based methods
55
Able to detect weak clots (low fibrinogen or factor XIII deficiency)
Mechanical clot end–based methods
56
May be confounded by icterus or lipemia
Photo-optical clot end-point detection
57
The ability to select reagents independently of the analyzer is a high priority
Open reagent systems
58
Keep records of reagent lot numbers and expiration dates, on–board monitoring of reagent volumes with flagging systems, and reagent barcoding
Reagent tracking
59
Eliminates the need to separate the plasma into the secondary tube
Primary Tube Sampling
60
Instruments often accommodate multiple tube sizes
Primary Tube Sampling
61
Placement of the primary blood collection tube without removing the blue stopper (the cap is pierced by a needle in the instrument that aspirates plasma)
Closed–Tube Sampling
62
Eliminates cross-over between specimens
Closed–Tube Sampling
63
Reduces the risk to the staff of specimen exposure
Closed–Tube Sampling
64
Eliminates the need for the operator to perform tasks manually
Automatic Dilutions
65
Examples of Common POC Tests:
○ Whole Blood Activated Clotting Time (ACT)
○ Prothrombin Time/International Normalized Ratio (PT/INR)
66
Used the viscoelastic property of blood clotting
Thromboelastography
67
Provides information on the entire kinetic process of whole blood clot formation
Thromboelastography
68
Thromboelastography specimen
whole blood
69
Allows evaluation of interactions of platelets, erythrocytes, leukocytes, plasma coagulation factors, and plasma proteins
Thromboelastography
70
Assesses both bleeding and thrombosis risk
Thromboelastography
71
Provides an evaluation of fibrinolysis and a hypercoagulable state
Thromboelastography
72
TEG Thrombelastograph Hemostasis analyzer system from haemonetics
Specimen
Reagent
Specimen: Nonanticoagulated or citrated WB
Reagent: Kaolin
73
As the blood clots, the resulting pin torque generates an electrical signal from the torsion wire
TEG Thrombelastograph Hemostasis
analyzer system from haemonetics
74
A new version of thromboelastography
Rotational Thromboelastometry (ROTEM)
75
Upon clot formation, the increased tension from fibrin binding the cup to the pin is detected by sensors
Rotational Thromboelastometry (ROTEM)
76
Platelet Function Testing:
1. Classic Platelet Aggregometry
2. Whole Blood Aggregation by Impedance
77
Platelet Function Testing:
Uses the light transmittance principle by Born
Classic Platelet Aggregometry
78
Platelet Function Testing:
Measure the increase light transmission that occurs in direct proportion to platelet aggregation
Classic Platelet Aggregometry
79
Platelet Function Testing:
Induced by various agonists
Classic Platelet Aggregometry
80
Platelet Function Testing:
Upon activation, platelets become sticky and adhere to metal sensor wires (electrodes)
Whole Blood Aggregation by Impedance
81
Platelet Aggregometers
Three calculated parameters:
○ Maximum percentage aggregation
○ Area under the curve
○ Velocity
82
Platelet Aggregometers:
A. PAP–8E from BioData
B. Chrono-Log
C. Multiplate Analyzer from Diapharma
D. AggRAM from Helena
83
Is an eight-channel platelet aggregometer with a touch screen and on-screen procedure templates
PAP–8E from BioData
84
Uses LTA and a low sample volume
PAP–8E from BioData
85
PAP–8E from BioData sample
PRP
86
Has a whole blood/optical lumi–aggregation system
Chrono-Log
87
Chrono-Log sample:
WB or PRP
88
Provides for platelet aggregation (impedance) and measures platelet secretion (optical density) response
Chrono-Log
89
Also called Whole–Blood Multiple Electrode Platelet Aggregometer (MEA)
Multiplate Analyzer from Diapharma
90
Monitors platelet function by impedance
Multiplate Analyzer from Diapharma
91
Correlate well with LTA in testing therapeutic efficacy
Multiplate Analyzer from Diapharma
92
A modular system for platelet aggregation and ristocetin cofactor testing
AggRAM from Helena
93
AggRAM from Helena Use laser diode measuring at a wavelength of
650 nm
94
Platelet Function Analyzers
1. Siemens PFA-100 Platelet Function Analyzer
2. Verify Now from Accriva Diagnostics
3. Plateletworks Platelet Function Assay (Helena)
95
Automated instrument that provides rapid results on quanti- and qualitative platelet abnormalities
Siemens PFA-100 Platelet Function Analyzer
96
Test cartridges stimulate platelet aggregation using collagen/epinephrine or collagen/ADP
Siemens PFA-100 Platelet Function Analyzer
97
Measures the time for a platelet plug to occlude a microscopic aperture
Siemens PFA-100 Platelet Function Analyzer
98
Successful in detecting von Willebrand disease and assessing aspirin therapy efficacy
Siemens PFA-100 Platelet Function Analyzer
99
Optical detection system measuring platelet aggregation by microbead agglutination.
Verify Now from Accriva Diagnostics
100
Uses disposable cartridges with fibrinogen-coated beads and platelet agonists.
Verify Now from Accriva Diagnostics
101
Provides aspirin assay, glycoprotein IIb/IIIa inhibitor assay, and P2Y12 inhibitor assay
Verify Now from Accriva Diagnostics
102
Results available in about 10 minutes, suitable for near-patient testing
Verify Now from Accriva Diagnostics
103
Can be run on any standard impedance cell counter.
Plateletworks Platelet Function Assay (Helena)
104
Aggregation results based on platelet count before and after activation
Plateletworks Platelet Function Assay (Helena)
105
Results obtainable in 2 minutes, ideal for presurgical screening and antiplatelet therapy monitoring
Plateletworks Platelet Function Assay (Helena)
106
Requires minimal specimen volumes, suitable for pediatric and difficult-to-draw patients.
Flow Cytometry
107
Able to measure multiple cellular activation-dependent changes related to platelet function
Flow Cytometry
108
Available for the diagnosis of heparin-induced thrombocytopenia (HIT), but currently laboratory developed tests (LDTs)
Flow Cytometry
109
are widely used for their accuracy in detecting point mutations and single-nucleotide polymorphisms.
Polymerase chain reaction (PCR)-based assays
110
while less common, is another method for analyzing PCR products
Restriction fragment-length polymorphism (RFLP) analysis
