MLP II Unit 3: Hematology

Erythrocytes (RBCs)

• Main function is carrying oxygen from lungs to the rest of the body

• Also carry CO2 back to lungs to be exhaled

• Main constituent of RBCs is hemoglobin

  • Hemoglobin is made up of iron + protein

  • Hemoglobin is what carries O2 and CO2

• Small, round, biconcave disk

• Area of central pallor

• Lifespan of about 120 days

Leukocytes (WBCs)

• Primary function is to protect the body against disease

• 5 types:

  • Segmented Neutrophil

  • Lymphocyte (T & B cells)

  • Monocyte

  • Eosinophil

  • Basophil

Segmented Neutrophils

• Make up large percentage of WBCs in the body

• Main function is phagocytosis — eating foreign pathogens

• Can migrate to the tissues to eat pathogens

• Increase in these cells on a differential indicates bacterial infection

Eosinophils

• Pink/red on blood smear

• Primary function is to protect against allergic reactions and parasitic infections

Basophils

• Have dark purple granules that contain heparin and histamine

• Involved in allergic/anaphylactic reactions — granules release heparin & histamine which causes smooth muscle contraction, vasodilation, edema, bronchospasms in anaphylactic reactions

Monocytes

• Largest WBC in the peripheral blood

• Mono in peripheral blood, macrophage when it migrates to the tissues

• Primary functions are phagocytosis and antigen presentation

Lymphocytes

• Other predominant WBC in the body

• Function is to provide immunity

• Increase in lymphs indicates viral infection

• Two types:

  • T cells — secrete chemical messengers that tell other cells what to do & kill virally infected cells

    • Cell-mediated immunity

  • B cells — make antibodies to provide immunity

    • Humoral immunity

• Natural Killer (NK) cells are large granular lymphs and are the first line of defense against tumors — they can kill without prior exposure to an antigen

T cells

• Two types:

  • Helper T cells secrete cytokines to tell other cells what to do

  • Cytotoxic T cells kill virally infected cells

B cells

• Must first be exposed to an antigen before they can make antibodies

• Once exposed, B cells remember that antigen and produce antibodies against it

• Next time person is exposed, antibodies attack the antigen before it can cause infection

• Called humoral immunity

Thrombocytes (platelets)

• Fragments of an actual cell called a megakaryocyte

• Main function is clot formation

• Work along with 30 different clotting proteins (found in the plasma) to promote coagulation

• Deficiencies in platelets or coagulation factors can cause major problems (ex: hemophilia)

Anemia

• Insufficient healthy RBCs and/or HGB to carry adequate O2 to cells and tissues

• Most common blood disorder in U.S.

• Etiology (varies by type)

  • Inadequate vitamins or minerals needed to produce RBCs (inadequate intake, malabsorption, or increased demand)

  • Acute or chronic blood loss

  • Chronic illness

  • Medication, NSAIDs, contraceptives, anticonvulsants, antineoplastics)

  • Bone marrow suppression r/t toxins, chemo, radiation (aplastic anemia)

  • Destruction of RBCs (hemolytic anemia, Sickle Cell anemia)

• Symptoms

  • Weakness

  • Fatigue

  • Shortness of breath

  • Pallor

  • Tachycardia

  • Numb or cold hands and/or feet

• Diagnosis

  • Medical history & PE

  • Lab

    • CBC (HGB, HCT, reticulocyte count r/t bone marrow function)

    • Peripheral smear: RBCs look smaller and pale

    • Serum iron

• Treatment

  • Correct nutrient deficiencies

    • Iron (ferrous sulfate)

    • IM B12 (lack of intrinsic factor secreted by stomach needed for B12 absorption

    • Treat underlying conditions

    • Stop bleeding

    • Replace RBCs (transfusion)

Leukemia

• Cancer affecting bone marrow (myeloid tissue)

• WBCs mutate quickly

  • Crowd out normal cells

  • Do not provide adequate immunity

• Etiology

  • Unknown

• Risk factors

  • Family history of leukemia

  • Prior tx for CA (chemo/radiation)

  • Exposure to radiation or chemicals

  • Smoking (AML)

• 4 main types — based on two criteria

  • Speed of progression

    • Acute: immature cells, rpaid onset, fast progression, aggressive tx

    • Chronic: mature cells, slower onset

  • WBC affected

    • Myelogenous: bone marrow cells that become RBCs, WBCs, and PLTs

    • Lymphocytic: lymphocytes

• Symptoms

  • Fatigue

  • Dyspnea

  • Chronic fever, chills, night sweats

  • Unexplained weight loss

  • Frequent infections, slow wound healing

  • Swollen, non-tender lymph nodes (especially neck and armpits)

  • Enlarged liver (Hepatomegaly)

  • Enlarged spleen (Splenomegaly)

  • Abnormal bleeding, bruising, petechiae

  • Bone pain

  • Additional symptoms if organs affected

• Diagnosis

  • History identifying risk factors & sx

  • PE revealing fever, wt loss, pallow, bone pain, enlarged lymph nodes, hepatomegaly, splenomegaly

  • Lab: CBC

  • Tissue bx of lymph nodes

  • Bone marrow bx

• Treatment: usually by hematologist-oncologist; depends on type and stage

  • Chemo and/or radiation

  • Biological therapy: meds to boost immunity

  • Targeted therapy: PO med imatinib (Gleevec) for CML

  • Bone marrow transplant

  • Stem cell transplant (stem cells in bone marrow become blood cells)

    • Diseased bone marrow exposed to radiation or chemo, then stem cells transplanted from healthy donor

• Prognosis

  • Depends on type and stage at diagnosis

  • If fatal, cause is usually infection

Hemophilia

• Rare bleeding disorder in which blood doesn’t clot normally (little or no clotting factor)

• Etiology

  • Usually genetic (mother to sons)

  • Two main types (A and B)

  • Most common is type A (missing factor VIII); type B (missing factor IX)

  • Rarely, hemophilia can be acquired if antibodies form against clotting factors

• Symptoms

  • Excessive bleeding (internal or external)

    • Procedures (circumcision)

    • Bleeding from mouth (losing a tooth)

    • Nosebleeds

    • Bleeding from minor cut

    • Hematuria, melena

    • Large bruises (bleeding into large muscle)

    • Bleeding into joints

    • Bleeding in brain

• Diagnosis

  • Pt history

  • Lab

  • Hemophilia A and B are classified as mild, moderate, or severe, depending on amount of clotting factor

  • Severe hemophilia (usually dx during infancy)

  • Pregnant carriers: in vitro; only embryos tested neg for hemophilia are implanted

• Treatment

  • Replacement therapy: concentrates of clotting factor VIII (for hemophilia A) or clotting factor IX (for hemophilia B) IV

  • Human blood or recombinant clotting factors

Hematology testing

• CBC is the most common hematology test

• Includes:

  • Hgb

  • Hct

  • RBC count

  • RBC indices (MCV, MCH, MCHC)

  • WBC count

  • WBC diff

  • Plt count

• Other common hematology tests:

  • Prothrombin time (PT)

  • Activated partial thromboplastin time (aPTT)

Hematocrit

• Measurement of the percentage of packed RBCs in a volume of blood

• Can either be done as a part of CBC or as a microhematocrit

• Normal range: 36-45% (women)

• Decreased in: Anemia

• Increased in: Polycythemia vera

Hemoglobin (Hgb)

• Measures O2-carrying capacity

• Can either be done as part of a CBC or POCT

• Normal range: 12-16 g/dL (women)

• Increase: Polycythemia vera

• Decrease: Anemia

• H&H must agree according to the rule of 3

  • Hgb x 3 ±3 = Hct

WBC count

• Counts the TOTAL number of WBCs in sample (all 5 types)

• Normal range: 4,000-11,000/mm3

• Increased (leukocytosis) in bacterial infections

  • Can also indicate diseases like leukemia

• Decreased (leukopenia) in viral infections, chemotherapy

WBC diff

• Tells us the percentage of each of the 5 types of WBCs

• Increased segs = possible bacterial infection

• Increased lymphs = possible viral infection

• Increased eosinophils = allergic reaction/parasitic infection

• Abnormal cells can indicate diseases like leukemia

• Also look at size & shape of RBCs & PLTs

PLT count

• Normal range is 150,000-400,000/mm3

• Decrease means patient may have trouble with blood clotting

ESR

• Not specific for particular disease

• Used as a general indicator of inflammation — can help monitor effectiveness of treatments

• Increased in infections, RA, Multiple Myeloma, lupus, and more

• Fill designated tube completely to line, invert several times

• Place in machine for 60 minutes, machine will print results

• CLIA-Waived

Coag testing

• Protime (PT) is most common — measures how many seconds it takes for blood to clot

• Used to diagnose hereditary bleeding disorders and monitor pts on Coumadin (warfarin) which slows the liver’s production of clotting factors

• INR was created to standardize PT results because they can vary depending on the reagent used in the test

• Widely accepted as the standard for reporting PT results

• Normal INR: 1-1.4

• Patients on medication to prevent blood clots will have higher INRs (2-3)

• Can be done on a coag analyzer or POCT

  • If done on analyzer, draw BLUE tube and fill to line!

Specimen collection

• Most tests are performed on a well mixed EDTA tube, whole blood

• Mix sample well after collection to evenly distribute EDTA — failure to do so will result in clotting

• If clotting occurs, you cannot report the results

  • PLT count will be low and WBC may be high, analyzer will flag

Blood smear

• Can be done on EDTA OR fresh capillary blood

• Depending on time constraints, MA may do this

• A good blood smear should cover ¾ of the slide and have a feathered edge

  • No ridges, holes, lines, clumps, streaks

  • Let air dry before staining

• Stain with Wright stain (series of 3 stains)

Immunohematology (Blood Bank)

• ABO

  • Involves transfusion of donor blood to recipient

  • Four major blood types

    • A — A antigens on RBCs

    • B — B antigens on RBCs

    • AB — A and B antigens on RBCs

    • O — lack of A or B antigens on RBCs

  • Antibodies are naturally made to the ABO antigens you lack!

  • YOU ONLY MAKE THE ANTIBODY IF YOU LACK THE ANTIGEN!

• Rh

  • Patient is either Rh positive or negative:

    • Presence of D antigen = Rh pos (85% of population)

    • Absence of D antigen = Rh negative (15% of population)

  • Antibodies are NOT naturally made to the Rh blood group

  • You only make antibodies if you lack the antigen & are then exposed

  • Ex: mom is Rh neg, baby is Rh pos, mom is exposed to baby’s blood & makes an antibody

    • Next pregnancy, if baby is Rh pos, mom’s Anti-D will cross the placenta and attack baby causing miscarriage or fetal anemia

    • To treat this, we give Rh neg moms Rhogam (Anti-D) to prevent mom from making it on her own

Blood transfusions

• ABO and Rh typing are usually performed before blood transfusion (only not performed in emergencies)

• Then, the lab tests donor blood with recipient serum to determine whether the recipient will react to donor blood (Crossmatch)

• Most blood transfusions come from another person, but a person can donate their own blood to be given later (after surgery) — autologous donation

• There is always a risk for bloodborne pathogens, but donor blood undergoes rigorous testing via FDA guidelines to minimize the risk

• Some religions do not believe in blood transfusions (Jehovah’s Witness) so MA should be aware of this and always ask consent