Chapter 11: Special Collections and POCT

Recom. for suspected bact/fungemia with persistent neg. cultures

Use alternative media - Myco/F lytic media bottle

How and why is Hb tested in POCT?

Used for managing anemia -Microcuvettes using any kind of blood specimen

What is the most critical aspect of blood culture collection and infection diagnosis?

Volume (and proper antiseptic technique) -volume more imp. than timing in diagnosis -id pathogen increases proportionally to V of blood cultured

Volar surface of the forearm

Where TB PPD test is given volar = pertaining to palm or sole =portion of the forearm that is on the same side as the palm of the hand

How are most skin tests performed?

With intradermal (within skin) injection of allergenic sub. - to determine if an ind. has come in contact with a specific allergen (antigen) and dev. antibodies to it. 1) skin prick test = puncture/scratch test for everyday allergens 2) TB test; bec. many dis-microbes function as allergens Positive response for TB would mean exposure in the past/infection through seeing the bodies immune response to the sub.

Tests performed by POCT device: Cascade POC

aPTT/PTT -screen for bleeding disorders prior to surgery -investigate known bleeding or clotting disorders -detect clotting factor deficiencies -monitor low-dose heparin therapy

With air

aerobic

Without air

anaerobic

Donating blood for one's own use

autologous

Rec. antiseptic for BC on >2 months and older and iodine sensitive?

chlorhexidine gluconate

Decreased blood sugar level

hypoglycemia

Ionized form of Calcium

iCa2+

Microorganism and toxins in blood

septicemia

Special?: Blood alcohol test

special chain of custody protocol required

Antimicrobial removal device

ARD - BC bottle that contains a resin that removes antimicrobials from blood - to use to test people who are currently on antibiotic therapy

Device used for ABG testing

AVOXimeter

What is the result of Incompatible donor/recipient blood mixing?

Agglutination - clumping - and lysis of RBCs within recipients circulatory system

Tincture of iodine antiseptic process for pediatrics

All other antiseptics same as on adults but this. Clean 2 times with sep. prep. pads of 70% isopropyl or ethyl alcohol

AST

Alternate Site Testing AKA - POCT i.e. bringing lab to the patient

How many blood cultures does the ASM (?) say are required for diagnosing bacteremia and fungemia?

American Society of Microbiologists: 2-4; each consisting of 2 blood culture bottles from a single ven. site

In TDM, what class of drugs is timing of draw most critical for?

Aminoglycosides; they have very short half lives -i.e. less critical for drugs with longer half lives

CPD

Anticoag and preservative often in solution in BB donor collection bags: Citrate = prevents clotting Phosphate: stabilized pH Dextrose - provides energy to cells to keep them viable A - sometimes included CPDA1 = adenine

Which of the following tests would not be subject to therapeutic drug monitoring? a) Theophylline b) Phenylalanine c) Gentamicin d) Digitoxin

B

FAN

Fasctidious antimicrobial neutralization; BC bottle that contains activated charcoal which helps to neutralize antibiotics to allow for microbe diagnosis

Lookback

Fed program that requires that all units collected at BB and their components must be traceable. ** occurs when blood service is made aware that there may have been a transfusion-related infection

FUO

Fever of Unknown Origin

Cell salvaging

Form of autologous donation done during surgery: recovers blood lost while surgery performed and re-infuses it back into patient. ** recommendation: blood be tested for residual hemoglobin to make sure that not too many RBCs were destroyed during recapture process - this could result in renal dysfunction

Test to diagnose carbohydrate metabolism problems

GTT: Glucose tolerance test AKA: OGTT - oral glucose tolerance test Tests for hypo-and hyperglycemia Length: after measured dose of glucose, measure response: -gestational: 1 hour -other: 3 hours

Hormone detected in pregnancy test

HCG = human chorionic gonadotropin - produced by placenta and found in urine and serum ~ 10 days after conception. Peak at 10 weeks. -kits with reagent and controls

What is the tester that could be used during cell salvaging?

HemoCuePlasma/Low Hemoglobin analyzer

HbA1c

Hemoglobin compound produced when glucose becomes chemically linked to hemoglobin Pr = glycosylation Rate of formation proportional to plasma GLU amts. and occurs at a steady rate over 120-day life cycle of RBCs = glycosylated Hb levels reflect average BGL over previous 2-3 months=can be used to evaluate long-term effectiveness of diabetic therapy Recomd 2X year, quarterly for those not regularly measuring their BGL

What is one main reason that BCs should not be drawn from IVs or arterial catheters?

High contamination rate of lines from VADs - infections in indwelling lines come HAI. If VADs used. One should be from VAD and the other percutaneously

Increased blood K+ levels

Hyperkalemia

Increased blood Na+ levels

Hypernatremia

Standardized form of PT results

INR: International Normalized Ratio INR = (PT patient / PT normal)ISI - international sensitivity index -dev. to standardize differences of test results between variety of PT devices/reagents CoagChek XS

Special?: RNA

If not tested immediately, must be collected with a stabilizing reagent

Outcome of hypoventilation

Increased CO2 = production of more H+ ions and may lead to acidosis

This analyte level marks severity of metabolic acidosis

Lactate

LTT

Lactose Tolerance Test; performed like GTT but replacing lactose subbed for glucose. Lactose intolerance = no mucosal lactase = relatively flat curve HAS mucosal lactase = similar curve to normal GTT

Program to trace blood unit components to donor

Lookback

Hypoxemia

Low oxygen level in the blood

Rupturing, as in the bursting of a RBC

Lysis

Role of Chloride

Mainly in extracellular space as NaCl or hydrochloric acid -if hypokalemia occurs, K+ and Cl- need to be infused

Special?: Paternity testing

May require photo ID before collection

Special?: Urine druge screen

May require proctor present at time of collection

Special?: Zinc

Must be drawn in trace-free element tube

National Institute on Drug Abuse

NIDA

Where are donor unit's collected from?

Normally a large antecubital v ** Must be collected from ONE site. If site selected only partially fills bag, it must be tossed and started all over again at a new site

Special?: GTT

Requires serial collection of blood specimens at specific times

Besides diagnosis of an MI, what else is Cardiac TnT POCT also used for?

To monitor thrombolytic therapy

Special?: Polycythemia

Treatment often involves removal of units of blood

Lowest serum drug concentration expected

Trough level

Activated Clotting Time

ACT: POCT-analyzed test of activity of the intrinsic coagulation factors -used to monitor heparin therapy Cascade POC

What is platelet function testing used for, and what device does it?

-Det. pts response to meds before open heart surgery or cardia cath - to prevent excessive bleeding or clots -det. response to antiplatelet meds - response to aspirin therapy VerifyNow System

Recom. for "second site" BCs

-Status of patient will determine timing. - second set from opposite arm (if possible) separately prepared. Sometimes will be 30-60 minutes apart

5 Preps for GTT

1) 3 days before test: eat balanced meals ~ 150 g carbs 2) 8-16 hrs before: fast; drinking water during fast and testing 3) no excessive exercise 4) no smoking or gum chewing - both trigger digestive responses 5) all tests must be performed same way - all venipuncture, or cap. *If vomiting occurs, Doctor must be consulted

What are the 2 agencies involved in setting guidelines for BBs?

1) AABB - quality assurance 2) FDA - blood products are considered pharmaceuticals

2 analytes measured in POCT for MIs

1) Cardiac TnT - rises within 4 hours and may stay elevated for up to 14 days 2) Cardiac TnI - rises 3-6 hours after MI, returns to normal in 5-10 days

ID/DOC Requirements for 2 types of blood alcohol tests

1) ETOH; for medical reasons, only requires standard protocol - though it still could be used legally 2) BAC - blood alcohol concentration required by law enforcement or employer: requires chain of custody

For trace element testing, recommendation for collection

1) ETS: by itself 2) syringe - Change transfer device before royal blue

4 reasons a person might undergo molecular genetic testing

1) ID presence of certain genetic disease 2) determine risk for part. disease 3) determine drug and dosage suitability 4) examine whole genome for genetic alterations that may cause disease

Tubes used for molecular genetic testing

1) Lavender: sterile, WB specimens 2) white top gel from Greiner 3) ACD, sodium citrate, sodium heparin *cannot be frozen, hemolyzed, or clotted *MAY be stabilized with reagents, refrigerated up to 7 days

5 common electrolytes tested by POCT

1) Na+ - most plentiful electrolyte in the blood 2) K+ 3) Cl- Chloride 4) HCO3- (bicarbonate ion) 5) iCa2+ = ionized calcium

The 5 components a unit of blood can be broken down into

1) RBCs 2) plasma 3) granulocytes 4) platelets 5) coag factors *all must be traceable to donor

Trace element tubes (4)

1) Royal Blue - EDTA special trace free tube 2) OR Lavender EDTA 3) Green heparin 4) red no additive

3 reasons why intermediate BC collection is not rec?

1) SPS increases final concentration of SPS 2) transfer = another chance for contam. 3) exposure risk to staff

Tubes used for blood drug screen specimen collection

1) alcohol: glass gray top sodium fluoride (with or w/o anticoag) filled until vacuum exhausted, stopper never removed (alcohol is volatile) 2) synthetic stims: light blue 3) inhalants and DNA analysis: lavender

What additives does a BB collection bag contain?

1) anticoag 2) preservative solution * on a mixing unit while being drawn

3 Eligibility factors for autologous donation

1) at least 72 hours prior to surgery/need (usually done several weeks before) 2) written doctor's order 3) hemoglobin at least 11 g/dL or crit => 33%

6 STAT tests that many multiple-test panel POCTs do and why and where

1) blood gas values 2) BUN 3) lactate 4) hemoglobin 5) glucose 7) potassium WHY? These analysts exist in the body within narrow safe ranges, and when/if they are not normal it can be quickly fatal. WHERE? ER, ICU

What 5 factors determine donor eligibility?

1) brief physical exam 2) extensive medical history - interview 3) Hbg: >= 12.5 g/dL 4) crit = 38% 5) written permission of donor * blood tests to be performed ea time a person donates, no matter how many times or how often they donate

3 ways to inoculate BC bottles

1) direct - butterfly 2) syringe 3) intermediate - yellow top SPS (this is an anticoagulant and also decreases complement Pr action on infectants)

BC bottle filling using butterfly

1) fill aerobic first = air in tubing will go in first and not effect test results 2) fill anaerobic second - air will have been pushed out already

BC bottle filling using a syringe

1) fill anaerobic first 2) fill aerobic second = air bubble will be the last thing in the bottle, so it doesn't matter if it goes into the aerobic one

What are 4 proven benefits of TGC?

1) lower infection rates 2) quicker healing 3) decreases length of hospital stays 4) lower cost of care

What is the role of sodium in the blood (3) ?

1) maintaining osmotic pressure 2) pH 3) transmitting nerve impulses

4 reasons a specimen collected for BB testing can be rejected

1) not labeled properly/exactly 2) grossly hemolyzed 3) contain IV fluid 4) collected longer than 72 hrs before

What type of analysis do UA specimens undergo?

1) physical 2) chemical 3) microscopic

Role of potassium (6) ?

1) usually concentrated in cells, very little in bones or blood 2) released into blood due to cell damage 3) nerve conduction 4) muscle function 5) pH 6) osmotic pressure

What is the wt requirement to donate blood?

110 pounds.

Test used to screen for diabetes and gestational diabetes?

2 hour PP -also used to monitor insulin therapy

Recommendation for diagnosing acute condition requiring rapid admin. of antibiotics

2-3 blood cultures, one right after another from dif. sites immediately after occurrence

Recom. for diagnosing FUO

2-3 blood cultures, one right after another from different sites -if neg. after 24-48 hours, do 2 more *BCs using ordered imed. before or during fever spikes when bacteria are most likely to be present. V still more important than timing

In a normal person, when does BGL peak?

30 minutes to hour; trigger release of insulin and comes down to fasting level ~ 2 hours and results in NO urine spillover

Antiseptic/Sterile technique

30-60 s friction rub (to get bacteria under dead skin to the surface) using: -tincture of iodine -chlorhexidine gluconate -povidine/70% ethyl alcohol combo *tincture or chlor. proven more effective than povidone-iodine SWAB: place at site of needle insertion and move in outward concentric circles covering at least 2.5 X 2.5 in. area -most common chlorhexidine gluconate/isoproply alcohol - due to iodine sensitivities and 30 second scrub

Special?: PT

9:1 tube ratio = collection V must be correct for correct results (light blue)

What is the age requirement for donating blood?

>=17 (in most states), 16 in some states with parental permission <=66 at discretion of BB MD

Which of the following should be removed from a list of drugs of abuse? a) Phenobarbital b) "Crack" and "ice" c) Amphetamines d) Cannabinoids

A

Collection unit for BB donation

A sterile, closed system -bag to contain blood -connected by tubing to 16-18 gauge needle -fills by gravity by being placed lower than the patient's arm

Organization that sets guidelines for blood donor centers

AABB

Tests performed but AVOXimeter

ABGS: 1) pH - normal = 7.35-7.45 2) pCO2 - indicates quality of air exchange 3) oxygen saturation = sO2 - percentage of Hgb binding sites occupied by oxygen in bloodstream -normal ~ 98% -<90% = hypoxemia 4) pO2 - evaluate lungs ability to diffuse O2 into alveoli into blood, and to monitor oxygen therapy

Blood Alcohol Concentration

BAC

Measurement for congestive heart failure

BNP

What is the first objective measurement of CHF?

BNP -B-type natriuretic peptide = cardiac hormone produced by heart in response to ventricular V expansion and pressure overload - increases with increasing severity of CHF ALSO - measurement used to dif. between CHF and COPD

What is the antiseptic most commonly used when taking a specimen for ETOH?

BZK - benzalkonium chloride -some use povidine-iodine -if neither avail. use soap and water

Bacteria in the blood

Bacteremia

What is measured in a PPD test?

Bleb/wheal created by transdermal skin puncture, and the induration (hardness), measured 48-72 hours after injection Negative = induration absent or <5 mm in diameter Doubtful = induration between 5-9 mm in diameter Positive = induration 10 mm or greater in diameter OR 5mm or more in immunosuppressed

System implemented to prevent fatal BB/HCF errors

Blood bank ID bands, blood recipient patient ID systems; blood bank ID has stickers on it that are immediately put on all blood donated and all crossmatch or other testing tubes (lavender or pink top -or non-add red top) 1+ required, and all future component breakdowns. All have unique identifying numbers; BBID must remain on donor for 3 days

How is paternity determined?

Blood or buccal testing that determines probability that child's DNA was acquired from tested person through his/her DNA mapping.

What is the most common tests performed by BB?

Blood type and screen: ABO, Rh factor

Rule on amount of blood collected

By weight, but usually ~ 450 mL

Identify the condition in which a unit of blood is withdrawn from a patient as a treatment. a) ABO incompatibility b) Autologous donation c) Hemochromatosis d) Hemolytic anemia

C

The correct order in collecting a blood culture is: a) perform friction scrub, select equipment, perform venipuncture, cleanse bottle tops. b) select equipment, cleanse bottle tops, perform friction scrub, perform venipuncture. c) select equipment, perform friction scrub, cleanse bottle tops, perform venipuncture. d) cleanse bottle tops, select equipment, perform friction scrub, perform venipuncture.

C

This test can determine if an individual has developed antibodies to a particular antigen. a) Strep test b) Hematocrit c) Skin test d) Troponin T

C

Which of the following is a protein that is specific to heart muscle? a) ALT b) BNP c) TnT d) LDL

C

Which of the following must remain consistent throughout an oral glucose tolerance test (OGTT)? a) Arm used for the draw b) Size of ETS tubes used c) Blood specimen source d) Position of the patient

C

Which point-of-care blood analyzer uses a microcuvette instead of a test strip? a) Cascade POC b) Precision XceedPro® c) HemoCue HB201+ d) I-STAT System®

C

Nonspecific marker for inflammation

CRP = B-globulin in blood that responds to inflammation and future risk of cardiovascular disease hs-CRP can be used to aid in infection, tissue injury, and inflam. disorders

Besides sodium citrate, what other additives might a light blue tube have and why?

CTAD - citrate, theophylline, adenosine, dipyridamole -inhibit thrombocyte activation between collection and testing

heart muscle Pr elevated in 3-6 hrs after myocardial damage

Cardiac Troponin I = TnI Return to normal in 5-10 days

Heart mus Pr that may stay elevated for 14 days after myocardial damage

Cardiac Troponin T = TnT

Special protocol for forensic specimen collections

Chain of Custody

Ability to be favorably mixed together

Compatibility

In reading a patient's tuberculin (TB) test, there is an area of induration and erythema that measures 7 mm in diameter. The result of the test is: a) negative. b) positive. c) unreadable. d) doubtful.

D

What type of additive is best for collecting an ethanol specimen? a) Potassium EDTA b) CPD + adenine c) Sodium citrate d) Sodium fluoride

D

he POC instrument VerifyNow does platelet testing to: a) measure abnormal increase in thrombocytes. b) evaluate warfarin or heparin therapy. c) continuously check the glycemic index. d) determine response to aspirin therapy.

D

Outcome of hyperventilation

Decreased CO2 levels lead to alkalosis

Skin antisepsis

Destruction of microbes on the skin

Recommendations for limiting transferral of microbes through POCT devices

Disinfection of instruments with 10% bleach solution, made daily, or use of ind. wrapped EPA registered, one-use wipes

Pre-birth paternity testing

Done through taking amniocentesis sample or by chorionic villus sampling (projections in vascular tissue that have the same genetic makeup as fertilized eggs and become fetal portion of the placenta)

Special BC bottles used for pediatric and why

Due to common prev. exposure of children to broad spectrum antibiotics. 1) different formulation 2) different V (up to 4 mL) (1-4% of patient's total blood V rec.)

Instrument's electronic quality control check

EQC: used in POCT = enhanced instruments that can detect errors/problems, when the equipment itself isn't functioning properly (bad readings), and daily liquid checks **cannot control specimen collection and handling errors

Abbreviation for ethanol

ETOH

Guaiac

Occult Blood - in feces - through the peroxidase activity tested with POCT by using kits with controls FOR: Diagnosing and finding location of gastric diseases, colon cancer, and other DT issues

Testing performed at the patient's side

POCT = point of care testing

After a meal

PP = post prandial

Special?: Blood type and screen

Patient ID procedures are extra strict

Highest serum drug concentration anticipated

Peak level

POLs

Physicians office labs - where many tests including hematocrits are often tested in POCT

Special?: blood culture draw

Skin antisepsis critical to accurate test results

PPD

TB test- contains purified protein derivative

5 Reasons to have Therapeutic drug levels collected at specific times

TDM (therapeutic drug monitoring) 1) to establish dosage 2) adjust dosage in combo with other drugs 3) ID noncompliance 4) maintaining therapeutic dosage 5) avoid drug toxicity * when taking drugs, blood is collected during peak and trough times to ensure therapeutic dosage is always maintained while not going into toxic range

Intensive insulin therapy for GLU control

TGC - tight glycemic control -taking frequent readings of a patient's glucose levels (like every .5 hour) along with insulin admin. to keep gLU levels in safe range

How does a POCT measure bilirubin?

Take optical density reading that show linear cor. with the serum total bilirubin concentration - by using light on meter on baby's head or sternum = noninvasive, no blood needed

Lead testing tube and additive

Tan - K2EDTA

Purpose of the crossmatch test?

Test compatibility of patient's plasma or serum and the donor's RBC mixed together