Mixing and Substitution Studies

Question 1

AKA Circulating Anticoagulant Screen, Screening for circulating Inhibitor

Answer 1

MIXING STUDIES

Question 2

PRINCIPLE OF MIXING STUDY

Answer 2

✓ PTT mixing study is indicated when the PTT is prolonged in the absence of heparin therapy (NOT Specific)
✓ The assay is preceded by a thrombin time to detect therapeutic heparin or a direct thrombin inhibitor
✓ A mixing study is performed by measuring the APTT in the patient’s plasma, then mixing an equal volume of the patient’s plasma and normal pooled plasma (NPP) and repeating the APTT tests immediately and after 37°C incubation.

Question 3

T/F. In Mixing Studies, Measure Patient’s APTT→Mixed an EQUAL volume of Patient’s Plasma & NPP→Measure APTT: immediately & Measure APTT: After 2-hours of Incubation at 37°C

Answer 3

True

Question 4

T/F. Substitution studies and factor assays can be used to identify specific coagulation factor deficiencies

Answer 4

True

Question 5

Substitution Studies Principle

Answer 5

• Substitution studies may be performed using adsorbed plasma and aged serum with the AP to identify deficiencies of blood coagulation
• Substitution studies may also be performed using adsorbed plasma with the PT to identify a factor VII deficiency

Question 6

FRESH PLASMA CONTAINS: PRESENT

Answer 6

ALL COAGULATION FACTORS

Question 7

AGED PLASMA
DOES NOT CONTAIN: (ABSENT)
CONTAINS: (PRESENT)

Answer 7

AGED PLASMA
DOES NOT CONTAIN: ABSENT (V, VIII)
CONTAINS: PRESENT (I, II, VII, IX, X, XI, XII)

Question 8

T/F. In AGED PLASMA FACTOR V & VIII decrease UPON STORAGE

Answer 8

True

Question 9

LABILE factor in AGED PLASMA

Answer 9

FACTOR V & VIII

Question 10

ADSORBED PLASMA
DOES NOT CONTAIN: ABSENT
CONTAINS: PRESENT

Answer 10

ADSORBED PLASMA
DOES NOT CONTAIN: ABSENT (II, VII, IX, X)
CONTAINS: PRESENT (I, V, VIII, XI, XII, XIII)

Question 11

FRESH SERUM
DOES NOT CONTAIN: ABSENT
CONTAINS: PRESENT

Answer 11

FRESH SERUM
DOES NOT CONTAIN: ABSENT (I, V, VIII, XIII)
CONTAINS: PRESENT (II, VII, IX, X, XI, XII)

Question 12

FACTOR II is ____ Present in fresh serum; _____ are consumed during coagulation

Answer 12

<20%; 80%

Question 13

entirely consumed during coagulation

Answer 13

OTHER COAGULATION FACTORS

Question 14

AGED SERUM
DOES NOT CONTAIN: ABSENT
CONTAINS: PRESENT

Answer 14

AGED SERUM
DOES NOT CONTAIN: ABSENT (I, II, V, VIII, XII)
CONTAINS: PRESENT (VII, IX, X, XI, XII)

Question 15

In AGED SERUM, It is Entirely consumed during coagulation

Answer 15

FACTOR II