MLS heme final quick guide

What happens during primary hemostasis?

Vasoconstriction- vessel contracts to limit blood flow to area and Platelet activation- platelet unstable fibrin clot forms

What does peritoneal (ascites) fluid surround?

The abdomen

What does pleural fluid surround?

The lungs

What does pericardial fluid surround?

The heart

Compare the automated vs manual cell counts for body fluids

Automated: preferred, dedicated BF mode, counts more cells, reproducible results, accuracy and precision, flagging. Manual: traditional, labor intensive, poor reproducibility, variability

Where is the CSF collected?

Via lumbar cord

What helps keep the microenvironment in check in bone marrow?

Stromal cells/fibroblasts

What happens during secondary hemostasis?

The coagulatin cascade→ stable fibrin clot forms

What happens during fibrinolysis?

Clot dissolution→ clot dissolves after healing

Anticoagulant in coag blue tops?

3.2% sodium citrate

Requirements for filling coag blue top?

Tube must be at least 90% full- 9 part blood: 1 part anticoagulant, gently invert tube immediately after filling 5x

In coag tops, if HCT >55%…

The anticoagulant must be adjusted to prevent falsely prolonged clotting times

Why do coag samples get rejected

If clotted, grossly hemolyzed, lipemic, icteric, or refridgerated

How soon do you have to test a PT?

Within 24 hours

How soon do you have to test an aPTT?

Within 4 hours

Laboratory tests for primary hemostasis

Platelet count and estimate, bleeding time, platelet aggregation studies, vWF: RCo and vWF: Ag, ristocetin induced platelet aggregation (RIPA)

Laboratory tests for secondary hemostasis

Prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin clotting time (TCT), reptilase time, fibrinogen assay, mixing studies, factor assays, DRVVT screen, urea solubility

Laboratory tests for fibrinolytic system

Fibrin degredation product (FDP) assay, d-dimer

Name of factor I

Fibrinogen

Does factor I require vitamin K?

No

Which pathway is factor I in?

Common

What converts factor 1 to fibrin

Converted to fibrin by thrombin

What is the name of factor II?

Prothrombin

Does factor II require vitamin K?

Yes

Which pathway is factor II involved in?

Common

What is the name of factor III?

Tissue thromboplastin

Which pathway is factor III involved in?

Extrinsic

Is factor III present in all tissues?

Yes, it is liberated by trauma

Name of factor IV?

Calcium (Ca2+)

Which pathway is factor IV involved in?

Intrinsic, extrinsic, common

Why must factor IV be replaced by reagents?

Because it gets bound by sodium citrate

Name of factor V?

Labile factor

Does factor V require vitamin K?

No

What pathway is factor V in?

Common

What factor deteriorates at room temp?

Factor V

Name of factor VII?

Stable factor

Does factor VII require vitamin k?

Yes

Which pathway is factor VII in?

Extrinsic

Name of factor VIII?

Antihemophilic factor

Does factor VIII require vitamin k?

No

Which pathway is factor VIII in

Intrinsic

What happens if factor VIII is deficient

Hemophilia A

Name of factor IX?

Christmas factor

Does factor IX require vitamin k?

Yes

Which pathway is IX in?

Intrinsic

What happens if factor IX is deficient?

Hemophilia B

Name of factor X

Stuart-prower factor

Does factor X require vitamin k?

Yes

Which pathway is factor X in?

Common

Name of factor XI?

Plasma thromboplastin antecedent

Does factor XI require vitamin k?

No

Which pathway is factor XI in?

Intrinsic

What happens if factor XI is deficient?

Hemophilia C

Name of factor XII

Hageman factor

Does factor XII require vitamin k?

No

Which pathway is factor XII in?

Intrinsic

Name of factor XIII?

Fibrin stabilizing factor

What pathway is prekallikrein and hig molecular weight kininogen in?

Intrinsic

Factor in extrinsic pathway

III, VII

Factors in the intrinsic pathway

Prekallikrein, HMWK, XII, XI, IX, VIII

Factors in the common pathway

X, V, II, I

Prothrombin time (PT) is used to screen deficiencies in…

The extrinsic and common pathways, I, II, V, VII, X

Prohrombin time reference range

11-14 seconds

Prothrombin time reagent

Tissue thromboplatin-calcium

Prothrombin time monitors which anticoagulant therapy

Coumadin/Warfarin

Activated partial thromboplatin time is used to screen deficiencies in…

Intrinsic and common pathways, I, II, V VIII, IX,X, XI, XII, PK, HMWK

Reference range of activated partial thromboplastin time

25-25 seconds

Activated partial thromboplastin time reagent

Phsopholipid-activator and calcium chloride

Activated partial thromboplastin time monitors which reagent

Heparin

The thrombin clotting time is used to screen deficiencies in…

Quantitative and qualitative deficienies in fibrinogen

Reference range of thrombin clotting time

10-22 seconds

Reagent in thrombin clotting time

Dilute thrombin

Which pathway do you assume an abnormality in if both PT and aPTT are both increased?

Common→ factors II, V, X

Which pathway do you assume an abnormality in if PT is normal and aPTT is increased?

Intrinsic pathway→ factors VII, IX, XI, XII

Which pathway do you assume an abnormality in if PT is prolonged and aPTT is normal?

Extrinsic pathway→ factor VII

Labs of vWF disease

Normal platelet count, prolonged bleeding time, variable aPTT, normal PT, decreased vWF:Rco and vWF:Ag, VIII:C

Aggregation pattern of vWF disease

Ristocetin: decreased/no response, normal response to ADP, collagen, epinephrine

Bernard-soulier syndrome labs

Defect in Gp ib-IX-V. Giant plts→ increased MPV, platelet anisocytosis→ increasedx RDW, prolonged bleeding time, PT and aPTT = normal, vWF:Rco, vWF:Ag and VIII:C normal

Lab findings of secretion defects

Generation of thromboxaine A2. Normal plt count, vWF: RCo and vWF:Ag normal,

What happens in immune thrombocytopenic purpura (ITP)

Patient forms autoantibody against platelet antigen, which are then removed from circulation by macrophages in the spleen

Labs of immune thrombocytopenic purpura (ITP)

Thrombocytopenia, PT aPTT and TCT normal, no anemia, no shistocytes

Immune thrombocytopenic purpura form in children

Acute form in children secondary to viral infection- transient and self limiting

What happens in heparin induced thrombocytopenia (HIT II)

Heparin induces conformation change in platelet factor 4 circulating on the platelet surface. Patient develops IgG antibody to heparin-PF4 complex. Immune complex triggers platelet activation and thrombosis can occur

Labs of heparin induced thrombocytopenia

Moderate thrombocytopenia, occurs >5 days after heparin exposure. Treatment: discontinue heparin and use another anticoagulation

What happens in neonatal alloimmune thrombocytopenia (NAIT)

Mother lacks plt ag present on fetal plts (usually HPA-1a), mother exposed to fetal platelet ag→ makes allo ab→ maternal ab crosses placenta and binds to fetal plts→ fetal plt with bound maternal ab crosses placenta removed from circulation by macrophages in fetal spleen. Intracranial bleeding: 25% of affected infants and can occur in utero

Peripheral blood smear of bernard-soulier syndrome

Giant platelets, thrombocytopenia, can be variable

Laboratory findings of glanzmann thromboasthenia

Defect. In GP IIb-IIa. Normal plt morphology, normal plt count, prolonged bleeding time, PT and aPTT normal

What happens in post-transfusion purpura

Patient makes allo Ab directed against an ag present on the transfused plts. Donor and patient plts removed from circulation by macrophages in spleen

What happens in drug-induced thrombocytopenia

Drug induces an antibody that reacts with platelets only in the presence of the drug. Drug binds to platelets and forms a drug-membrane protein complex; antibody forms to the complex. Drug induces autoantibody against a platelet antigen. Ab bound platelets removed from circulation

Three types of microangiopathic hemolytic anemias (MAHAS)

TTP, HUS, DIC

What causes thrombotic thrombocytopenic purpura?

Autoantibody against the vWF-cleaving protease, ADAMTS-13 causes platelet aggregation, thrombi and intravascular hemolysis

Labs, symptom, treatment of thrombotic thrombocytopenic purpura

Thrombocytopenia, anemia, neurological problems, normal PT, aPTT, TCT. Treat with plasma exchange

What is hemolytic uremic syndrome (HUS) associated with?

Associated with acute gastroenteritis and bloody diarrhea; usually associated with E. Coli O157:H7. Bacteria releases shiga toxins that have affinity for endothelial cells mainly in kidney, causing injury which active plt forming microthrombin

Labs of hemolytic uremic syndrome

Thrombocytopenia, anemia, renal failure, normal pt, aptt, tct

What happens in disseminated intravascular coagulation (DIC)

Activation and consumption of clotting factors and platelets throughout the vascular system. Activation of fibrinolytic system→ symptoms of bleeding and clotting

Labs of Disseminated intravascular coagulation

pt, aptt, tct all prolonged. Fibrinogen and platelets decreased. D-dimer increased. Soluble fibrin monomer= positive, tct and reptilase time prolonged. Anemia

What is DIC caused by

Tissue factor release into circulation, toxins (snake venom), platelet activation, and others

What happens in primary fibrinogen

Plasminogen is inappropriately activated to plasmin in the absence of clot formation. Caused by certain malignancies (prostate cancer) or massive tissue damage that causes release of plasminogen activators

Labs in primary fibrinogenolysis

Pt, aptt, tct all prolonged, decreased fibrongen, normal platelets and rbc morphology. Fdp increased, d-dimer normal

Main lab differences in DIC and Primary Fibrinogenolysis

DIC: decreased plt count, increased d-dimer, decreased antithrombin. PF: normal plt count, normal d-dimer, normal antithrombin