Chapter 11 Flashcards
What tube has its own special labeling
Blood bank (pink top)
What is a cross match
Cross match to determine the compatibility between patient plasma and donor cells
Blood donations are collected in
units
Donor eligibility requirements
minimum age of 17
weigh at least 110 pounds
physical exam and medical history
written permission from the donor
Lookback program
recipients can be notified if a blood donor is rejected for having a transmissible disease
federally mandated by the FDA
Autologous donation
allows patient to donate for themself
requires physician order
cell salvaging
Allows blood to be salvaged from sterile surgical field to be washed and reinfused to the patient
blood culture
collected and cultured in micro for the detection of bacteria or other microorganisms
used when bacteremia or septicemia is suspected or a fever of unknown origin
blood culture specimen requirements
Usually two to 4 collections drawn 30-60 minutes apart
* Minimum of 10 mL per collection
* Uses aerobic and anaerobic nutrient broth collection bottles
* Collect aerobic bottle if only enough blood for one bottle can be obtained
* Patients on antibiotics may require special collection bottles
skin antisepsis
- Contamination from skin flora is major concern* Adequate antisepsis is critical
- Use a 30-60 second rub with iodine, chlorhexidine or povidone/70% ethanol
- Povidone sticks traditionally used or pads with benzalkonium chloride
- Start at the point of needle insertion and move in small circles outward in a 3-4 inch diameter area
- Chlorhexidine may be used in infants over age 2 months and those with iodine sensitivity
Coagulation special collection
– A “clear” or discard tube is required for all coagulation tests except for PT or PTT
– A discard must is required when collecting with a butterfly because the air in the tubing displaces the vacuum in the collection tube
– Sodium citrate tubes must be filled until vacuum is exhausted
– Must have a 9:1 ratio of blood to anticoagulant
– NEVER pour two tubes together
– Some tests may require the specimen to be placed on ice
How does a 2-hour postprandial glucose work?
Patient fasts for 10 hours.
Fasting glucose is collected. Patient ingests high glucose (100 g of glucose) meal.
Glucose level is collected 2 hours after the meal.
Glucose level should return to near fasting levels in 2 hours in non-diabetic patients
How does a glucose tolerance test work?
– Patient eat a balanced diet containing 150g carbs daily and fasts for 12 hours before testing.
– Fasting glucose is obtained and patient drinks a beverage containing 75 g of glucose within 5 mins
– Glucose levels are drawn at 30 minutes, 1 hr, 2 hrs and 3 hrsand plotted on a curve
– Elevated levels at 2 hrs are diagnostic for diabetes
Lactose tolerance test
Patient consumes lactose then 2 hr GTT is performed. Curves should resemble GTT curve. Flat curve indicates lactase deficiency
Paternity/Parentage testing
Chain of custody must be maintained. Testing will include ABO typing, HLA typing and DNA profile of mom, baby and alleged father
Therapeutic phlebotomy
– Performed similarly to blood donor collection. Performed on patients with polycythemia (overproduction of RBCs) and hemochromatosis (excess iron stores in the body)
– Usually around 500 mL are removed
Therapeutic drug monitoring (tdm)
– Performed to assess the level of a specific drug to maintain a safe, effective level of the drug in the body
– May be random for medications taken daily
– Aminoglycoside drugs (gentamicin, tobramycin, vancomycin and amikacin) must be assayed at trough
– just before the dose is given – and peak levels
– Peak levels are assessed 30 minutes after an IV dose, 60 minutes after an IM dose, or 1-2 hours after an oral dose.
– Drug may be withheld if trough levels are elevated
– Some gel tubes may affect test results. Consult drug test package insert for specimen requirements
toxicology specimens
tests for the presence of a drug or toxin frequently with some legal ramifications
Forensic blood alcohol (ethanol) specimens
Specimen will be used in court; therefore, chain of custody must be maintained. May have to be collected in the presence of a law enforcement officer and may have to use their special collection kit
Clinical blood alcohol (ethanol) specimens
Can not use alcohol as an antiseptic. Should be collected in glass tubes(plastic is too porous). Tube should be filled to prevent evaporation and the stopper must not be removed until testing is performed. Results are generally not admissible in court.
Drug screening
usually urine specimen. Requires chain of custody. Performed for employment or sports participation. Most commonly looking for 7 major classes of drugs – amphetamines, barbiturates, benzodiazepines, cocaine, THC, opiates and phencyclidine (PCP). May also screen for propoxyphene(Darvocet) and methadone. May be on initial employment or can be done randomly. Room must be contained for the purpose of collecting urine drug screens
Trace elements
– Tests for aluminum, arsenic, copper, lead, iron, & zinc
– Measured in small amounts
– Collected in specially cleaned trace element-free tube usually royal blue stopper
Point of care testing
– Brings lab testing to location of patient
– Offers convenience to patient & short turnaround time
– Requires carrying out quality-control & maintenance procedures necessary to ensure that results are accurate
Quality and Safety in POCT
– Waived vs. non-waived quality control checks
– Electronic quality control (EQC) built into POC instruments
– Specimen collection & handling not checked by EQC
– Daily external liquid QC for non-instrumented POCT
– POC instruments become possible fomites for disease
Coagulation Monitoring by POCT
- Prothrombin time (PT) & international normalized ratio (INR)
- Activated partial thromboplastin time (APTT or PTT)
- Activated clotting time (ACT)
- Platelet function
POCT instruments
- Cascade POC —ACT, APTT, PT/INR
- CoaguChek XS Plus —PT/INR
- GEM Premier 4000 —ACT, APTT, PT/INR
- i-STAT —ACT, PT/INR
- Verify Now —platelet function
Arterial blood gases measured (POCT)
- pH
- Partial pressure of carbon dioxide
- Oxygen saturation
- Partial pressure of oxygen
Electrolytes measured (POCT)
- Sodium
- Potassium
- Chloride
- Bicarbonate ion
- Ionized calcium
Multiple-Test-Panel Monitoring by POCT
Commonly ordered stat tests such as blood gases, electrolytes, & hemoglobin
Other Tests Performed by POCT
– Cardiac troponin T & I
– Lipid testing
– B-type natriuretic peptide
– C-reactive protein
– Glucose
– Glycosylated hemoglobin
– Hematocrit
– Hemoglobin
– Lactate
– Occult blood (guaiac)
– Pregnancy testing
– Skin tests
– Strep testing
– Urinalysis
