Chapter 13: Specimen Collections and Special Procedures

1
Chapter 13Specimen Collections and Special
Procedures
2
Introduction

• There are special types of specimen collection
  procedures ordered by physicians, and
  phlebotomists should be familiar with them.
• Glucose testing is used to diagnose various types
  of diabetes.
• Timed specimens can detect changes in patient
  conditions, therapeutic medication blood levels,
  metabolism rates of substances, and to measure
  analytes exhibiting diurnal variation.

3
Glucose Testing

• The testing of glucose levels helps to diagnose
  diabetes mellitus, gestational diabetes,
  hyperinsulinism, and other related conditions.
• It is probably the most frequently ordered type
  of blood test.
• An increase in blood glucose may indicate the
  development of diabetes.

4
Timed Specimens

• Timed specimens are those collected at a specific
  time because timing of collection is critical for
  any of various reasons, including
• Monitoring changes in a patients condition.
• Therapeutic medication blood levels.
• Measuring metabolism rates of various substances.
• Measuring analytes that exhibit diurnal variation.

5
Timed Specimens

• Special patient preparation and timing may be
  required for certain laboratory tests, including
  those that test for the highest and lowest
  medication level times during the day.
• Other timed specimens include
• Glucose tolerance tests Iron levels
• Cortisol levels Hormone assays
• Cardiac enzymes

6
Therapeutic Drug Monitoring

• Specifics for therapeutic drug monitoring include
  correlation of timing for last dose and time of
  collection.
• Drugs that are monitored tend to have a narrow
  therapeutic index the blood level required is
  close to the level that causes significant side
  effects and/or toxicity.
• Rates of drug metabolism differ between
  individuals as well as over time.

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Indications for Therapeutic Drug Monitoring

• Knowledge of the drug level influences
  management.
• The drug dose cannot be optimized by clinical
  observation alone.
• There are potential patient compliance problems.
• There is an experimentally determined
  relationship between plasma drug concentration
  and the pharmacological effect.
• There is a narrow therapeutic window.

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Fasting

• The reference values or expected values published
  for many laboratory tests are determined from
  normal volunteers who are in good health.
• These volunteers are tested after abstaining from
  food and exercise for a short time.
• These states are referred to as fasting and basal
  state specimens, and are usually drawn first
  thing in the morning.

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Fasting

• Fasting is the most common timed specimen
  request, and means abstaining from food and
  beverages, except water, for 8-12 hours before
  the test.
• All strenuous activity should be avoided as well.
• It is important to avoid eating (fast) because
  glucose and triglyceride levels are affected by
  eating.

10
Lipemia

• Blood drawn shortly after a meal may appear
  cloudy (lipemic).
• Lipemia is caused by a large amount of fatty
  compounds in the blood after a meal, and
  interferes with many laboratory tests.
• When lipemia is severe, blood serum appears
  similar to milk instead of its normal clear
  yellow appearance.

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Bleeding Time Test

• The bleeding time test is used to evaluate
  platelet and vascular factors that are associated
  with hemostasis.
• The test is occasionally performed preoperatively
  to ensure adequate hemostasis.
• It measures the platelets ability to stop
  bleeding after an injury, and determines the
  ability of platelets to function.

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Performing the Test

• A special device may be used to achieve a
  bleeding time by making a standard 5-millimeter
  (mm) incision, which is 1 mm deep, on the
  patients forearm.
• Normal bleeding time is 2.5 to 9.5 minutes, but
  in many conditions this time can be more.
• These conditions include
• Decreased platelet number
• Platelet dysfunction
• Fibrinogen disorders
• Medications that change platelet function
  (aspirin, aspirin-containing medications,
  antihistamines, NSAIDs)

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Performance of the Bleeding Time Procedure

• To perform a bleeding time test, the patients
  arm should be placed on a steady support, with
  the palm facing up.
• Usually the test is performed on the ventral side
  of the arm, midway down the forearm.
• The puncture should be made about 2 centimeters
  (cm) distal to the antecubital fossa.

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Performance of the Bleeding Time Procedure

• If there are significant amounts of hair, the
  site should be shaved.
• A blood pressure cuff (sphygmomanometer) should
  be placed on the patients upper arm instead of
  using a tourniquet.
• The site should first be cleansed with an alcohol
  prep pad and allowed to dry.
• The bleeding time device should be removed from
  its packaging, and the safety clip removed.

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Performance of the Bleeding Time Procedure

• Avoid contamination of the device before use.
• Inflate the cuff to 40 mm of mercury the
  pressure should stay there for the entire
  procedure so that pressure is consistent.
• The device should be rested on the patients
  forearm parallel to the antecubital crease
  (across the arm), using minimal but firm pressure
  the ends of the device should just touch the
  skin.

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Performance of the Bleeding Time Procedure

• Simultaneously, push the trigger, which will
  slice the skin, and start the stopwatch.
• Timing begins from the puncture and continues
  until bleeding has completely stopped.
• Just after making the incision, remove the device
  and dispose of it into a sharps container.

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Performance of the Bleeding Time Procedure

• After 30 seconds, use filter paper to quickly
  absorb the flow of blood without touching the
  incision this causes clots to break apart.
• The incision should be wicked (absorbed) every
  30 seconds until flow stops.
• If bleeding continues for more than 15 minutes,
  stop the procedure and apply pressure, recording
  this occurrence.

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Performance of the Bleeding Time Procedure

• After removing the sphygmomanometer, clean the
  incision area.
• Apply a bandage while trying to pull the two
  sides of the incision together the bandage
  should be left in place for 24 hours.
• Bleeding times should be reported to the nearest
  30 seconds by checking the stopwatch to determine
  the result.

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Platelet Function Assay (PFA) Test

• The Platelet Function Assay (PFA) test is used to
  determine platelet adhesion and aggregation (also
  called primary hemostasis).
• This test is replacing the bleeding time test
  since that test is not useful in patients who use
  aspirin or NSAIDs, which alter the results.
• The PFA test only requires a simple venipuncture
  and is less invasive collection is made into 2
  light blue-topped citrate tubes.

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Blood Donation

• Phlebotomists perform blood donations, and the
  blood contains many products that may help save a
  life during blood transfusion.
• These products include
• Plasma Platelets
• RBCs Blood clotting factors
• Blood typing reagents Proteins
• Immunoglobulins
• Labeling must be completely accurate to that each
  unit is traceable to its donor.

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Blood Donation

• Not everyone is allowed to donate blood.
• Individuals must be between 17 and 66 years,
  weigh at least 110 pounds, and have a good health
  status.
• For minors, written parental consent is required.
• Hematocrit and hemoglobin levels should be high
  enough so that the donor is not harmed by the
  donation.

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Blood Donation

• Before donation, a complete health history and
  physical examination is required.
• Recent foreign travel and certain sexual
  activities may cancel a persons ability to
  donate blood.
• These questions screen for HIV and sexually
  transmitted infections (STIs).

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Blood Donation

• The blood supply available for transfusion must
  be kept safe.
• Staff members should inform donors that they will
  have a second chance to admit risky behaviors
  without any others hearing the information.
• After the initial screening is accepted, the
  donor is placed in a sitting or reclined position.

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Blood Donation

• Donation collects between 450-500 mL of blood,
  taking about 7 minutes.
• The skin is twice cleaned, in the antecubital
  area, and blood is collected in a sterile, closed
  collection system.
• This consists of a blood collection bag, tubing,
  and a 16-gauge needle.
• The blood flows via gravity into the bag, which
  is placed lower than the arm of the donor.

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Blood Donation

• The bag contains citrate phosphate dextrose, an
  anticoagulant.
• Its contents may be mixed by machinery or
  manually, and these sterile closed collection
  systems are only for single use.
• If the bag does not fill properly, for any
  reason, all of the components of the system must
  be discarded another complete system must be
  used for a second attempt.

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Blood Donation

• Blood donations for ones own future use can also
  be made, and are known as autologous blood
  donations.
• These can be kept on reserve for use within a
  specified time period.
• Health status must be stable, and hemoglobin must
  be at least 11 grams.
• If donating for an upcoming surgery, this must
  take place more than 72 hours from the time of
  donation.

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Blood Donation

• Patients must be monitored for dizziness, nausea,
  and other side effects.
• The donor should be kept in a reclining position,
  with the head lower than the heart.
• He or she should not walk or stand.
• After donation, the patient is given fruit juice
  or a small snack to keep blood glucose levels
  adequate.

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Therapeutic Collection

• Usually, therapeutic phlebotomy is used to treat
  polycythemia, a disease causing overproduction or
  abnormal increase in red blood cells.
• This condition can harm the overall health of the
  patient.
• It causes the heart and other organs to become
  very strained by attempting to circulate
  abnormally high amounts of cells.

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Therapeutic Collection

• Another condition using therapeutic collection is
  hemochromatosis, wherein the body stores abnormal
  amounts of iron.
• This condition can lead to serious health
  problems.
• Therapeutic collection of blood is undertaken to
  reduce the levels of iron throughout the body.

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Blood Alcohol Testing

• Blood alcohol levels may be requested by the
  police, such as in the case of driving under the
  influence (DUI).
• The patient must consent to having the blood test
  performed, and can refuse it.
• Employers may also request this test if an
  employee smells of alcohol or acts intoxicated.

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Blood Alcohol Testing

• Great care must be taken by the phlebotomist
  during collection since these specimens are often
  used for legal cases.
• The chain-of-custody of these samples must be
  closely monitored.
• When performed, the site from which blood will be
  taken must be cleaned by an appropriate
  disinfectant (fur example, chlorhexidine) instead
  of alcohol, since this could give a false
  positive.

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Forensic Specimens

• Forensic specimens, like legal specimens, must
  follow a special chain-of-custody procedure.
• Documentation must account for the specimen at
  every moment from collection until delivery.
• All handlers must sign and date a legal document
  to verify their participation.
• Forensic specimens must be kept in locked
  containers or sealed tubes so that unauthorized
  people cannot tamper with them.

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Types of Forensic Specimens

• The following are usually collected to prove or
  disprove links between individuals, objects, or
  places
• Blood Bones
• Hair Nails
• Saliva Skin
• Soil or mud Sperm
• Sweat Teeth
• Vegetation

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Collection of Forensic Specimens

• Documentation all specimen handling must be
  documented, usually on a chain-of-custody form.
• Gloves should always be worn when handling
  specimens to avoid contamination.
• Handling specimens should be packed, stored,
  and transported correctly, such as by
  refrigeration, humidity control, or room
  temperature.

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Collection of Forensic Specimens

• Labeling specimens should be labeled with
  patient name, birth date, name of person
  performing the collection, type of specimen, date
  of collection, and time of collection.
• Packaging packing of specimens should be secure
  and tamper-proof only authorized people should
  touch specimens.
• Timing collect specimens as soon as possible.

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Toxicology

• Toxicology is the basic science that deals with
  poisoning, particularly with the effects of drugs
  or other chemicals upon the intracellular
  function of tissues and organs.
• Toxicologists study how poisons act, and how they
  can be detected.
• It is vital to follow laboratory protocols when
  handling toxicology specimens to avoid
  contamination.

37
Drug Monitoring

• Therapeutic drug monitoring may be used by a
  physician to supervise a patients drug or
  medication treatment.
• Each patient requires different dosages to
  produce desired effects.
• Monitoring medication levels helps to establish
  beneficial levels for the patient, and also helps
  to avoid toxicity.

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Commonly Monitored Medications

• Antibiotics amikacin, gentamicin infections
• Anticonvulsants phenobarbital, phenytoin
  abnormal discharge of CNS electrical impulses,
  treating seizure activity
• Antidepressants chlorpromazine elevation of
  mood, treating depression
• Blood thinners heparin, warfarin heart
  conditions, coagulation disorders

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Commonly Monitored Medications

• Cardiac glycosides digoxin to increase
  strength of heart contraction, slow heart rate,
  treating heart failure
• Mood stabilizers lithium stabilization of
  mood swings, treating manic-depressive psychosis
• Xanthine derivatives theophylline opening of
  airway passages, treating asthma and bronchitis

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Peak and Trough Levels

• For therapeutic drug monitoring, specimens are
  obtained by routing venipuncture, but must be
  collected when medicines are at their highest
  serum concentration usually 15-30 minutes after
  being administered.
• This is known as the peak level.
• Trough levels are also collected, when serum
  concentration of medications are expected to be
  at their lowest level.

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Peak and Trough Levels

• Usually peaks and troughs are measured for
  antibiotics that are toxic at high levels, but
  not effective at lower levels.
• Drugs (such as antibiotics) with a short
  half-life make the time of collection more
  critical.
• The actual times that specimens are drawn must be
  documented.
• All drug monitoring specimens must be labeled as
  either peak or trough to signify the levels
  that were established correctly.

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Arterial Punctures

• Usually, arterial punctures are used to test
  arterial blood gases (ABGs), which measure the
  lungs ability to exchange carbon dioxide and
  oxygen.
• Results may show partial pressure of these
  substances in the arterial blood, as well as the
  pH level of the blood.
• Arterial puncture is usually not performed by a
  phlebotomist since it requires special training.

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Performance of Arterial Puncture

• Usually, arterial punctures are performed by
  members of the respiratory therapy department of
  a facility.
• Licensed personnel who are usually responsible
  for this includes nurses, physicians, medical
  technologists, and respiratory therapists.

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Steps for Performing Arterial Puncture

• Cleanse the skin at the puncture site with the
  alcohol swab.
• The patients hand should be bent back slightly,
  or a small rolled towel placed under the wrist.
• Palpate for the pulse with your index and middle
  fingers.
• Slightly anchor the artery with your index and
  middle fingers to prevent it from rolling when it
  is punctured.

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Steps for Performing Arterial Puncture

• The syringe should be held at a 45 degree angle
  or less in your opposite hand.
• This near parallel insertion of the needle
  minimizes trauma to the artery.
• While anchoring the artery, with the bevel turned
  upward, insert the needle to just under the skin
  surface advance it slowly until you notice a
  flashing pulsation of blood in the hub maintain
  this until you have collected 2 to 4 cc of blood
  in the syringe .

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Steps for Performing Arterial Puncture

• If you should advance the needle too far,
  withdraw it slowly until blood flows into the
  syringe you should not need to aspirate the
  blood into the syringe.
• After obtaining the desired amount of blood,
  withdraw the needle and apply pressure to the
  puncture site with the 4x4 gauge.
• After pressure has been applied for 2 minutes,
  check the site for bleeding, oozing, or seepage
  of blood apply pressure until all bleeding has
  stopped.

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Steps for Performing Arterial Puncture

• Remove the needle from the syringe.
• All needles should be placed in sharps
  containers.
• It is vitally important that air bubbles are
  removed from the blood gas syringe as they may
  alter the blood gas results.
• Hold the syringe upright and gently tap it so
  that air bubbles are forced to the top of the
  syringe where they can be expelled.

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Steps for Performing Arterial Puncture

• Cap the syringe and place the syringe in the bag
  of ice to prevent any further metabolism of
  blood.
• Attach the lab slip to the bag, and have it
  transported to the laboratory.
• If you are going to analyze the sample, you
  should do so as soon as possible.

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Venous Access Devices

• A cannula is a hollow tube that is inserted and
  left in a vein it is referred to as a venous
  access device.
• The most commonly used type for obtaining blood
  samples is called a heparin lock.
• This is a special winged needle set left in a
  patient's vein for between 48-72 hours.

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Heparin Locks

• Heparin locks are used when obtaining blood is
  difficult or the patient needs multiple draws
  over a short period of time.
• However, these locks are primarily used to
  administer certain medications.

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Cannulas

• The cannula must be periodically flushed with
  heparin or normal saline to keep clots from
  forming.
• If heparin is chosen, the first 5 mL must be
  discarded before collecting any specimens.
• Only specially trained personnel should do this.

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Shunts and Central Venous Therapy Lines

• Other venous access devices include shunts and
  central venous therapy lines.
• Arterial venous shunts are devices that are
  inserted into the forearm to allow hemodialysis
  to occur.
• The shunt is connected to a machine that filters
  the blood, as is often done for patients with
  severe kidney disease.

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Shunts and Central Venous Therapy Lines

• Central venous therapy involves introducing a
  cannula into a vein other than a peripheral vein.
• Phlebotomists usually do not perform these
  functions.
• Vascular access devices are defined as those that
  allow frequent access to a patients veins
  without using IV needles or other large catheters
  an example is a chemo port which is used to
  infuse chemotherapy.