Exam 1: Blood/Urine Testing

hemolysis

destruction of RBCs

Serum

liquid portion of the blood left over after RBCs clot

plasma

liquid portion of anitcoagulated whole blood

stopper-puncturing end

used for placing IV; no needle stays

bore

diameter of the inner wall of a needle

large needles

14-18 gauge; used for blood donation or mass transfusion

small needles

20-22 gauge; routine blood collection

Use of needles smaller than __ gauge is NOT appropriate in lab draws

22

evacuated tubes

"closed" collection system; air removed to create a vacuum that draws just enough blood

Plain Red or Gold tube

No anticoagulant; Chem and Serology testing

Gold (red/gray) tube "Tiger top"

SST; no anticoagulant; tests requiring serum; contains inert polymer gel that separates serum; most chem tests

Lavender tube

anticoagulant "EDTA" (ethylenediaminetetraacetic acid)

-inversion required

-used to check RBC, hematology, blood bank

Light blue tube

anticoagulant: sodium citrate

-inversion required

-Coag testing plasma and platelet function

-NO chem or electrolyte

Green tube

anticoagulant: heparin

-inversion required

-used for ABG, Chem analyses (troponin, ammonia)

heparin

in form of sodium, lithium, or ammonium salt

-enhances activity of antithrombin 3 that inhibits coagulation

-UNacceptable for blood cell evaluation

Gray tube

anticoagulant: potassium oxalate

-additive sodium fluoride

-glucose and BAC testing

not for electrolytes

Order of drawing labs

1. Sterile Specimens : blood cultures

2. Coagulation studies : light blue

3. No anticoagulant : red or gold (sst)

4. With anticoagulant : green, lavender, gray

Syringes are used for drawing blood on

patients with fragile veins (typically elderly)

butterfly infusion sets are used on

patients with small or fragile veins (peds and elderly)

tourniquet

flat latex-free rubber strip used to stop blood flow prior to blood draw

best place to draw blood

antecubital fossa anterior to elbow

antecubital fossa veins

1. Median Cubital (Middle)

2. Cephalic (Thumb)

3. Basilic (Pinky)

T/F if a. patient has an IV you can draw blood from the same arm

F: if a pt has an IV you MUST draw blood from the opposite arm

Arterial Samples are used for

ABG (blood gas)

-pH, pO2, pCO2

oxygen level is ___ throughout the body

uniform

arterial samples require

glass or gas-impermeable plastic syringe

anticoagulant for ABG

sodium heparin

what is the first choice location for arterial sample

Radial artery

what test must you perform before doing an arterial draw

modified Allen test

T/F Arteries are only used for samples

T: no lines can be placed

when would you do a capillary blood sample

quick glucose, infants, elderly, chemo, burn

equipment needed for finger prick

lancet

Heels are used for collection sites when

infants are under 15 months of age

when doing a finger puncture use the ___ hand

non-dominant

why should you not "milk" the puncture site

damages blood cells and can increase K

T/F you can use the first capillary drop of blood

F: always wipe away the first drop of blood

physiologic factors affecting venous samples

eating, strenuous exercise, emotional stress

effects of eating prior to labs

increased glucose and triglyceride levels

-CMP, BMP, Lipids

procedural factors affecting venous blood samples

extended contact between the serum and cells, hemolysis, clots formed in specimen, wrong pt, wrong time

-will have to redraw

random urine specimens

routine urinalysis

-UTI, renal function, metabolic/systemic disease

first morning urine specimen

collected immediately upon arising

-best for pregnancy tests

-must be delivered w/in 1 hour or refridgerated

clean-catch midstream urine specimen

clean genital area first; catch urine midstream

-WBCs present = infection

timed urine specimen

first void is not kept, all other urine for the time frame collected and stored in fridge

-keep track of collection time

refrigeration helps keep urine samples accurate because

it prevents bacterial overgrowth

turbidity

haziness

STAT testing

• Ex: troponin

• When results needed immediately

• Mostly inpatient or ED

• Only some tests can be ordered STAT from outpatient