Clin med exam 1 review

Which tubes have no anticoagulant?

Which tubes have no anticoagulant?

plain red/gold and tiger top (SST)

What tube for serology testing?

plain red/gold

What tubes for chemistry panels?

plain/red gold

What tube for hematology?

purple / EDTA

What tube for coagulation and platelet function?

light blue / sodium citrate

What tube for troponin?

green / heparin

What tube for ammonia?

green / heparin

what tube for blood bank testing?

purple / EDTA

what tube for acid-base imbalance?

green / heparin

what tube for arterial blood gasses?

green / heparin

what tube for blood alcohol testing?

gray / potassium oxalate

what tube for glucose?

gray / potassium oxalate

Serum

liquid portion of CLOTTED blood samples

(lack of free-floating clotting factors)

plasma

liquid portion of ANTICOAGULATED whole blood

(contains clotting factors/coagulation proteins)

What abnormalities are present when RBCs are hemolyzed in the sample?

increased level of serum potassium

RBC/WBC count is decreased

(inaccurate anemia and inaccurate electrolytes)

Which gauge needle is appropriate for venipuncture?

20-22 gauge

Which gauge of needle for blood donations or mass transfusions?

14-18 gauge

What size needle is not appropriate for routine blood collection? What are they used for?

smaller than 22 gauge (damages RBCs- hemolysis)

lidocaine, botox, small injections

Structure/Staffing of the clinical laboratory department

medical director- supervision & management, usually a pathologist

laboratory officer- administrative direction & quality control data, usually a medical technologist

testing personnel- medical technologist (MT) &medical laboratory technicians (MLT)

phlebotomists and laboratory assistants- specimen collection, basic lab procedures under supervision

What artery is most commonly used for arterial blood sample?

Radial artery in the wrist (FIRST CHOICE)

What PE test is necessary before using the radial artery for an arterial blood sample and why?

Modified Allen Test- to determine adequate circulation through ulnar artery.

In case radial artery is damaged, ulnar artery will still adequately circulate through the hand.

In the event that the radial artery cannot be used for arterial blood samples, what artery could you use instead?

brachial artery near basilica vein in antecubital area

How does eating affect venous blood samples?

increases serum glucose and triglyceride levels

What tests are performed after the patient has fasted?

CMP, liver functions

glucose and triglyceride/ lipid tests

What tests are elevated due to strenuous exercise/

How does strenuous exercise affect venous blood samples?

increases LD, CK, serum creatine, potassium, and WBC count.

Increased hematuria and proteinuria may be observed

How does emotional stress affect venous blood samples?

falsely increase WBC cont

How does hemolysis affect venous blood samples?

increases serum potassium, magnesium, phosphorous, LD, and acid phosphatatse

decreases RBC count and abnormal RBC indices

24 hour urine specimen collection

- first void is not kept. time is recorded.

- collect all urine voided over 24 hour time period

- last void at end of time period added to total volume

*must be refrigerated during collection to avoid bacteria overgrowth*

Types of urine tests

24 hour - quantitative procedure for analytes (protein, creatinine, calcium, cortisol)

random urine- routine urinalysis (UA); UTI, pyelonephritis, renal function, metabolic/systemic diseases

first morning urine - pregnancy test (inc. hCG)

clean catch midstream - microbiology (urine culture, antibiotic sensitive testing UCx)

What are the effects of improper urine storage?

inc bacterial growth, nitrite, pH, turbidity

dec glucose, ketones, bilirubin, urobilinogen

disintegration of cells, casts, crystals

color change

Causes of anemia?

increased destruction of RBCs - hemolytic anemias

decreased production of RBCs - aplastic anemias

excessive blood loss

aplastic anemia

destruction in bone marrow / failure to produce RBCs normally

pancytopenia

abnormal depression of all cellular elements of blood

-penia vs -cytosis/-philia

-penia: dec in number of cells

-cytosis / -penia: inc in number of cells

hematopoesis

formation of RBCs

hematopoesis locations

after birth, bone marrow is the only site

• birth-20 years: long bone

• after 20 years: flat bones, vertebrae, pelvis

Peripheral blood smear

-EDTA anticoagulated blood on glass slide stained with Wright-Giemsa stain (purple)

-examined for WBC types & percentage, abnormal RBC morphology, platelet count estimate and clumping

How are reference ranges determined?

collect from large population and determine range

erythrocyte vs leukocyte vs thrombocyte

erythrocyte- red blood cell

erythrocyte- white blood cell

thrombocyte- platelet

WBC differential

stained with wrights stain then identified and classified w/ microscope

result report as relative count (percentage of each type)

• Never Let Monkeys Eat Bananas

  • neutrophils

  • lymphocytes

  • monocytes

  • eosinophil

  • basophil

reticulocyte

polychromatic erythrocyte (immature RBC)

matures in 1-2 days in periphery

what does reticulocyte count indicate?

RBC production in bone marrow

seen in peripheral samples

What increases retic count?

-hemolytic anemias (sickle cell anemia, G-6-PD deficiency, autoimmune antibody formation)

-acute or chronic bleeding

-following treatment for iron deficiency anemia

-following treatment of factor deficiency anemias (hemophilia a/b, von willebrand’s disease)

What decreases retic count?

-aplastic anemia

-ineffective erythropoiesis

reticulocyte appearance with wrights stain

more than considered normal

stain differently than mature rbcs

Erythrocyte Sedimentation Rate (ESR)

detects inflammation

very non-specific

replaced with C-reactive protein (CRP) at most facilities

What causes increased destruction of RBCs?

What does tissue hypoxia result from?

reduced oxygen carrying capacity of carboxyhemoglobin / decrease in oxygen delivery to body tissues

What does tissue hypoxia cause? Which organ and hormone?

****in kidneys- stimulates inc erythropoietin production

Lifespan of RBC

120 days

Where does destruction of RBCs occur?

by macrophages in spleen

RBC indices

MCV- size of cell (always 80-100)

MCH- weight of Hgb per cell

MCHC- concentration of Hgb per cell

RDW- range of sizes of cells

term for increased variability of cell sizes on peripheral smear?

anisocytosis

Microcytic

MCV less than 80

Normocytic

MCV 80-100

Macrocytic

MCV greater than 100

most common cause of megaloblastic anemia

low vitamin B12 and low folate

Which RBC indices is indicative of megaloblastic anemia?

MCV >100 (macrocytic)

What do toxic granulation and vacuoles indicate?

acute bacterial infections

What type of cell is this and what does it indicate?

Reactive lymphocyte- abundant, pale blue staining unevenly, appears “soft” and is easily indented by surrounding RBCs, abnormally shaped and borders less defined

indicates viral infections (infectious mononucleosis, hepatitis, pneumonia, mumps, etc), pertussis (whooping cough), toxoplasmosis

absolute leukocyte count

WBC ct x leukocyte diff

Megakarocytes

produces platelets through megakaryopoiesis

(CFU-Meg/stem cell → megakaryoblast → magakaryocyte → platelets)

C-reactive protein test

why is G6PD deficiency significant?

exposure of RBCs in affected persons to oxidizing drugs causes RBCs to lyse (hemolytic anemia)

What is a bone marrow aspirate indicated for?

assess amount and nature of cell growth and maturation (uses red bone marrow from pelvis)

used to diagnose polycythemia vera, acute and chronic leukemias, myelodysplastic syndromes, aplastic anemia

how is anemia classified

based on RBC morphology- size and color intensity

what RBC morphology is associated with hereditary spherocytosis

spherocytes (appear microcytic and hyper chromic due to loss of central pale area)

stomatocytes (rectangular or slit-like central pale area)

what RBC morphology is associated with G6PD deficiency

helmet/bite cells, blister cells (looks as if bite was taken out of it)

what RBC morphology is associated with DIC

schistocytes (small, bizarre shaped cell fragments)

what RBC morphology is associated with sickle cell crisis

schistocytes (small, bizarre shaped cell fragments)

what RBC morphology is associated with severe burns

schistocytes (small, bizarre shaped cell fragments)

what RBC morphology is associated with multiple myeloma

rouleaux (stack of coins/ partially adhering to each other)

What is left shift and how is it determined?

neutrophils present in blood are at a slightly earlier stage of maturation than usual. results in an increased number of band neutrophils (bandemia)

indicates acute bacterial infection

What is hemoglobin composed of?

spheroid protein composed of 4 global chains (1 pair of alpha or zeta chains, one pair of non alpha chains - delta, beta, epsilon, gamma) with 4 heme molecules that bind and transport 4 O2 molecules

What 3 parts are needed for hemoglobin synthesis to occur? what stage in erythropoesis does it occur?

dependent on: adequate iron delivery and supply, adequate synthesis of heme molecule, adequate globin chain synthesis

begins in the Rubricyte (polychromatophilic normoblast) stage of RBC maturation (right before nucleus ejection)

carboxyhemoglobin

hemoglobin - carbon monoxide complex

comprises very low concentration of normal hemoglobin

Elevated in CO poisoning → tissue hypoxia causes cherry red blood

methemoglobin

hemoglobin in which Fe2+ (ferrous iron) is oxidized to Fe3+ (ferric iron) resulting in molecule that’s unable to transport oxygen

pathophysiology of Hgb SS (defective hemoglobin molecule )

forms when polymers which damage RBC membrane resulting in the sickle cell shape when RBC is deoxygenated

sickle cells cannot travel through small capillaries resulting in vast-occlusion, tissue hypoxia, etc

thalassemia

blood disorder when body doesn’t make enough Hgb

difficult to diagnoses, best study is genetic testing

alpha thalassemia

lack of alpha chain production

beta thalassemia

reduced or absent beta chain production

elevation of Hb F may indicate, elevation of Hb A2 level confirms diagnosis

best test to evaluate HGB abnormalities

hemoglobin electrophoresis

purple tube - EDTA

Where is the majority of iron in the body?

hemoglobin contained in RBCs (70%)

How is iron transported? What are the storage forms?

transferrin transports iron

storage forms- ferritin (soluble form) and hemosiderin (insoluble form)

best test to evaluate iron body stores

serum ferritin level

What are the causes of Fe deficient anemia?

chronic blood loss (GI bleeding/heavy menstruation)

increased body iron usage (pregnancy, lactation)

inadequate dietary iron intake

decreased iron absorption (intestinal disorders, post-small bowel resection, vit c deficiency)

What will you see on iron study labs for IDA (iron deficient anemias)?

dec serum iron

inc TIBC

dec trans-ferrin

dec serum ferritin

dec or absent body iron stores

pathophysiology of sideroblastic anemia

defective incorporation of iron into heme molecule- iron insertion into porphyrin ring prevented

inherited- rare sex-linked disorder, or acquired- alcohol abuse, lead poisoning, drugs that inhibit B6

results in accumulation of iron in mitochondria of RBC precursors

dec iron available, dec hemolgobin and hematocrit

hemochromatosis

inherited autosomal recessive disorder which results in idiopathic increase of iron absorption in intestine

slow, chronic build up of iron, accumulates outside of RE cells causing injury to parenchymal cells

porphyria cutanea tarda

most common porphyria (enzyme defect in heme synthetic pathway)

sun exposed areas develop blisters (vampire)

heme intermediates accumulate in tissues

petechiae

small pinpoint intradermal hemorrhage; <2 mm diameter

represent extravasation of blood into skin

stays bright red until healed

purpura

group of petechiae; (2mm-1cm)

can be palpable or non-palpable

ecchymosis

intradermal hemorrhage(s), larger than purpura often referred to as “bruises”; greater than 1cm

turns yellow/green when healing

What is exposed during an injury to the bloodstream to start the coagulation process?

subendothelium

How does aspirin affect platelets? 

prevents platelets from signaling each other by blocking receptor sites

results in platelet inactivation

reduces number of platelets that adhere to injury site

Which studies assess platelet function?

bleeding time

platelet count

platelet closure time

How do platelets and vonWillibrand factor interact?

reduction of platelet adhesion

Which factors are vitamin K dependent?

factor II- prothrombin

factor VII- stable factor

factor IX- Christmas factor

factor X- Stuart-prower factor

Which factor is the starting point of the common pathway?

factor X- Stuart-prower factor