Phleb - Unit 5 Special Blood Collection Procedures

what equipment is used for microcapillary collection

Lancets

BD microtainer tubes (0.2-0.5 mL)

why might microcapillary collection be performed

patient doesn’t have adequate veins → small child or infant

point of care testing (checking blood often, glucose)

where are collection sites for microcapillary collection

fingers

heels

what is the compositions of capillary blood

Capillaries, arterioles, and venules meet

mixture of arterial, venous, and capillary blood along w/ interstitial fluid

microcapillary collection - fingerstick procedure

greet and identify patient

put on gloves

position supplies

cleanse site

perform puncture (middle or ring finger, just off the center of the finger pad)

wipe off first drop of blood

fill collection container(s)

gauze and apply pressure to site

dispose of lancet

label specimens

band-aid

remove gloves and wash hands

Thank the patient - deliver specimen

where should microtainer be positioned to collect blood from finger

positioned directly beneath puncture site, patient palm down

order of draw for microcapillary blood containers

1. gas tubes

2. slides

3. EDTA (purple top tube) - platelets

4. Heparin (light or dark green top tube)

5. Serum (red top or amber tube w/ red top)

essential to minimize the effects of platelet clumping

procedure for filling microhematocrit/ microcapillary tubes

hold tube horizontally against drop and fill w/o introducing air spaces

plug opposite (dry) ends w/ caps or clay

neonatal collection - heelstick procedure

identify patient

put on gloves and warm the heel

position supplies

choose the site

• must exercise care to avoid damaging the heel

perform puncture

wipe away 1st drop of blood

fill containers

place gauze, apply pressure, and elevate the heel

DO NOT APPLY BANDAGE

ensure bleeding has completely stopped (5-10 s; bleeding beyond 5 min report to physician)

dispose of lancet

remove gloves and wash hands

thank the patient, parent, or guardian - deliver specimens

microcapillary collection - coagulation samples

light blue-top tubes for coagulation tests must be filled to minimum fill line

• 9:1 ratio of blood:anticoagulant

If using a butterfly needle a discard tube must be collected first to prime the tubing

• failure to use a discard tube will result in an incorrect ratio of blood:anticoagulant

should partially filled tubes be combined to make a full tube?

no, never

note: most lab policies state that an individual can only attempt two draws→ under such situation, have another phleb collect the sample

blood culture

diagnostic for bacteremia and septicemia

collect blood before or during fever spikes

perform venipuncture w/ butterfly (syringe is also acceptable)

aseptically prepare site for venipuncture → sterility is the most important part of collection

Blood culture - site preparation

perform 30-60 s friction scrub w/ Chloroprep (chlorhexidine gluconate, CHG)

• some facilities use tincture of iodine

allow site to air dry

while site is drying, inspect bottles for visible defects, check expiration dates, and remove flip-off caps

cleanse the culture bottle tops using 70% isopropyl alcohol (DO NOT USE IODINE)

allow to air dry

what are the ways blood culture can be collected?

collected using butterfly needles into:

• a 30 mL syringe or

• directly draw into bottles using holder

what bottle in blood culture should be collected first when using butterfly needle?

aerobic bottle

butterfly tubing has air in it

how do syringe draws work for blood culture?

syringe must be removed to attach a transfer device

culture bottles are inserted in the same manner as tubes

bottles must be mixed by inversion as soon as they’re removed from the holder

what bottle in blood culture should be collected first when using needle and syringe?

anaerobic bottle first, then aerobic bottle

air bubbles rise to the top of the syringe barrel → pure, air-free blood sits at tip and is pushed out first

anaerobic bottles go first to completely block any trapped air from entering the O2 free environment

blood culture - optimum vol. for adults vs. children

adults: 8-10 mL per bottle

peds: 1-3 mL per bottle

blood culture - optimum number of bottles for adults vs. peds

Adult: one culture includes 1 aerobic and 1 anaerobic bottle

patients <30 lbs should have one pediatric bottle collected

blood culture - short draw rule

if the draw is difficult, and you realize you can’t get the full 16-20 mL needed for both bottles, prioritize the aerobic bottle only, and put all available blood into it (up to 10 mL)

-most bacteria that cause infection are aerobic

What is the Glucose Tolerance Test (GTT) used for

screening for type 2 diabetes and gestational diabetes

GTT/ OGTT (oral glucose tolerance test) procedure

patient fasts overnight ← first specimen

baseline (fasting) glucose is drawn

the patient is given a determined dose of glucose to drink (75-100 g)

• adult dose: 75 g

• children= 1 g/kg of body weight

• pregnant women= 50-100 g

blood is then collected (timing specified by clinician) at:

• 2 hrs for Type 2 diabetes screening in adults

• 1 hr for low-risk pregnant women (50 g glucose bev is given)… sometimes called oral glucose challenge test (OGCT)

• 1, 2, & 3 hours for high risk pregnant women or women positive in the 50 g screening stage (100 g glucose bev is given)

Paternity Testing

performed to determine or exclude paternity

chain of custody protocol and form

photo ID of all parties - mother, child, alleged father

blood samples of buccal (cheek swabs)

Chain of custody

chain of custody

documentation tracking the specimen from time of collection until results are reported

identifies all individuals that collected, handled, transported, and tested specimen

if documentation is incomplete, legal action can be compromised

Therapeutic Drug Monitoring (TDM)

establishes and maintains drug dosage at therapeutic level and avoids drug toxicity

typically used for drugs w/ narrow therapeutic ranges

Trough (minimum)

• 30 min or just prior to administration of drug

• w/i the therapeutic range

Peak (maximum)

• after giving the drug; varies w/ drug and method of administration, times will be noted on the requisition

  • 30 min, 60 min, or 120 min

legal specimens

typically for toxicology or forensic studies such as drug screen, alcohol analysis, or DNA testing

Chain of custody form (CCF)/ Custody and Control Form (CCF) required

• patient identification and collection require a witness (such as law enforcement officer, corporate rep, or authorized medical staff member

Blood alcohol (ethanol) specimens - physician ordered for treatment purposes

chain of custody not required, follow standard protocol

Blood alcohol (ethanol) specimens - ordered in connection to on-the-job injury, employee insurance programs, and employee drug screening

chain of custody required

skin prep: do not use alcohol-based disinfectant

specimen requirements: gray-top sodium fluoride tube; fill tube until vacuum is exhausted and do not remove stopper

employee drug screening

required by many healthcare organizations, sports associations, and major companies

may be random

may detect a specific drug or screen for up to 30 drugs

typically performed on urine rather than blood

Chain of custody (CCF) is required

does physician request have to be documented for every instance of HIV testing?

exception is for needlestick/splash exposures → imperative to get tested immediately

what information must be given in Delaware before HIV testing

explanation of test — purpose, potential uses, limitations, meaning of results

explanation of procedure

explanation about AIDS and other manifestations of HIV infection

risk behaviors for transmission of HIV infection

Point of Care Testing - Blood Glucose Monitoring

utilized to monitor glucose levels in diabetic patients and determine insulin coverage

variety of monitors

proper training is required for each monitor

TIMING IS CRITICAL

POCT - Capillary Blood Gases (CBGs)

pH, partial pressure of CO2, oxygen saturation, and partial pressure of oxygen

rarely collected on adults (done for infants and young children)

warming the site for 5-10 min before collection is necessary to increase blood flow and arterialize the specimen

Seal both ends of the capillary tube after collection of the blood

POCT - electrolytes

sodium, potassium, chloride, bicarbonate ion, ionized calcium

usually in STAT situations (e.g. ED) or in ICUs

several types of handheld or mobile testing devices

POCT - Cardiac markers/lipids

troponin - myocardial infarction (MI)

BNP (B-type natriuretic peptide)

• Congestive Heart Failure (CHF)

• Chronic obstructive pulmonary disease (COPD)

CRP (C-reactive protein) - inflammation

Lipid panels - CHOL, TRIG, LDL, HDL