Term
| What is the purpose of the lab & clinical pathology? |
|
Definition
1) Confirm/reject Dx
2) Guide patient management
3) Eastablish prognosis/stage
4) Detect occult disease
5) Monitor therapy
6) Estimate disease activity
7) Prevent irreparable damage |
|
|
Term
| What lab protocols must implicitly be followed in order to provide quality lab values? |
|
Definition
1) specimen collection
2) handling
3) processing |
|
|
Term
| What are the 3 settings lab results can be generated from? |
|
Definition
1) Clinical lab
2) POC (point of care)
3) physician's office |
|
|
Term
| When is POC testing appropriate? |
|
Definition
| actue condition in which changes are rapid s.a. ER or OR |
|
|
Term
| What is the advantage to POC testing? |
|
Definition
| provides "real time" results |
|
|
Term
| Who provides the guidance and training for POC testing? |
|
Definition
| clinical lab (they're also responsible to maintain quality control & quality improvement) |
|
|
Term
| What are the tests able to be performed at the physician's office? |
|
Definition
The "waived tests" - easy to perform technically s.a.:
-pregnancy
-rapid flu
-rapid strep
-mono-spot |
|
|
Term
| Why can't physician's offices perform tests beyond the "waived" scope? |
|
Definition
| CLIA 88 = amendment issued by Congress to closely regulate lab testing |
|
|
Term
|
Definition
| physician (written or direct order) |
|
|
Term
| What does the physician's order of test generate a list for? |
|
Definition
|
|
Term
| What must be contained on the order for testing? |
|
Definition
Patient's demographics:
-name
-sex
-age
-DOB
-date of admission
-date of test request
-hospital number
-ordering physician |
|
|
Term
| What 6 things must be considered that the patient can do that may influence lab determinations? |
|
Definition
1) Diurnal variations
2) Physical activity
3) Fasting Status
4) Chronic EtOH
5) Postural changes
6) Drug regimen |
|
|
Term
|
Definition
| variations that occur every day |
|
|
Term
| What 2 daily serum infiltrates have diurnal variation? |
|
Definition
1) Cortisol
2) Neutrophil count |
|
|
Term
| What is the nature of the diurnal variation of cortisol? |
|
Definition
| Highest in morning & lowest around midnigh for ppl w/ normal sleep pattern |
|
|
Term
| What causes the diurnal variation of cortisol? |
|
Definition
|
|
Term
| What is the nature of the diurnal variation of neutrophils? |
|
Definition
highest around 4 pm in ambulatory patients, lowest in the morning @ rest.
There is significant individual variation (some who display NO dinural variation) |
|
|
Term
| How does physical activity affect lab values? |
|
Definition
1) Transient increase in some enzymes (CK, AST, LD)
2) Long lasting effect on some lipoproteins |
|
|
Term
What serum values may change at a 48 hr fast?
72 hours? |
|
Definition
48 hrs:
biliribun increase slightly
72 hrs:
hypoglycemia
increase triglycerides
increase fatty acids |
|
|
Term
| How long should a person fast prior to lab tests to provide an evaluation of the basal rate? |
|
Definition
|
|
Term
| What happens if a patient chooses not to fast & has a small meal prior to lab tests? |
|
Definition
| may affect several parameters including fat, protein, & serotonin |
|
|
Term
| What serum parameters are affected by chronic EtOH use? |
|
Definition
incrase HDL, cholesterol, & some liver enzymes
incease in MCV (mean corpuscular volume) |
|
|
Term
| How can postural changes affect lab values? |
|
Definition
| proplonged standing or sitting can cause loss of intravascular fluid due to increased hydrostatic pressure. |
|
|
Term
| What serum levels may be affected by postural changes? |
|
Definition
increased albumin & total protein
increased sm. moleculed bound to serum proteins
increased Hb, Hct & PMNs |
|
|
Term
| What drugs do we expect to see adjusted lab values with? |
|
Definition
| 1) Cholesterol lowering drugs to affect LDL
2) heparin to prolong aPTT
3) several drugs affect K+ values (up or down)
4) some drugs may have intrinsic properties that affect the assay itself adjusting the numbers |
|
|
Term
| What do the colors of the blood collection tubes mean? |
|
Definition
What is contained in the tube:
Anticoaglulant? Which one? |
|
|
Term
| What color means there's NO additive to the blood collection tube? |
|
Definition
|
|
Term
| Why would an anticoagulant be used? |
|
Definition
| to test whole blood or plasma after reparation from the red cells |
|
|
Term
|
Definition
| coagulated blood (plasma with no clotting factors) |
|
|
Term
|
Definition
| no coagulation (to assess cellular or coagulation factors) |
|
|
Term
| Why wouldn't an anticoagulant be used in blood collection? |
|
Definition
| allow the blood to clot & serum to separate |
|
|
Term
| Why must serum or plasma be separated from RBCs? |
|
Definition
| prevent an increase in chemicals & enzymes found intracellular |
|
|
Term
| Why is it important to know if blood was collected from a vein or an artery? |
|
Definition
| v. & a. differ in oxygen content, pH, CO2, hematocrit |
|
|
Term
| What is the source of most blood collection? |
|
Definition
|
|
Term
| What are the steps for proper collection of a venous puncture? |
|
Definition
1) patient ID
2) cleanse area
3) application/removal of tourniquet
4) invert tubes containing anticoagulant for mixing
5) proper disposal of sharps
6) check on patient status after draw
7) label tubes |
|
|
Term
| How many times should you attempt a draw before asking for help? |
|
Definition
|
|
Term
| What are the possible complication of venipuncture? |
|
Definition
hematoma
excessive bleeding
thrombosis of vein
infection (rare) |
|
|
Term
| Why is it important to remove the tourniquet at the appropriate time? |
|
Definition
| prolonged application can cause hemocencentration => higher Hb & hematocrit |
|
|
Term
| When might a skin punture be used as opposed to a venipuncture? |
|
Definition
| pediatric patients (infants) |
|
|
Term
|
Definition
| heel prick is made following 5-10 min exposure to warm water |
|
|
Term
| What values cannot be obtained in a skin puncture? |
|
Definition
|
|
Term
|
Definition
| catheter into vein or artery eliminating need for multiple draws |
|
|
Term
|
Definition
drug & fluid administration
drawing blood |
|
|
Term
Function
Arterial catheter |
|
Definition
| allow continuous, real time monitoring of blood gases & acid base balance |
|
|
Term
| What artery is usually used in arterial catheters? |
|
Definition
|
|
Term
| Hore catheters kept open? |
|
Definition
| heparin, therefore there is need to draw 3-6 mL of blood PRIOR to your actual blood collection if needing cogaulation values |
|
|
Term
| What are the 4 problems associated with blood collection? |
|
Definition
1) short draw
2) hemolysis of blood sample
3) oxylate & citrate can inhibit amylase, lactic dehydrogenase, & acid phosphatase activity
4) sodium & potassium salts in anticoagulant can give false sodium or potassium values |
|
|
Term
|
Definition
| dilution due to increased ratio of anticoagulant |
|
|
Term
| When drawing multiple tubes, is there an order to the draw? |
|
Definition
| Yes, draw the non-additive tubes first (unless blood cluture draw- which should be first) |
|
|
Term
| Why accounts for 1/3 of sample processing time? |
|
Definition
|
|
Term
| Why shouldn't blood samples be agitated during tansportation? |
|
Definition
|
|
Term
| Why shouldn't blood samples be exposed to light? |
|
Definition
| to avoid breakdown of analytes (i.e bilirubin) |
|
|
Term
| How are unstable constituents of the blood sample transported? |
|
Definition
|
|
Term
| What lab processes must be done prior to sample analysis? |
|
Definition
| centrifugation, aliquoting & distribution (50% of lab time) |
|
|
Term
| How are patient's IDed in the lab? |
|
Definition
|
|
Term
| How are lab results released? |
|
Definition
| technician checks the results and the automated system interface releases the analysis to the hospital computer system |
|
|
Term
|
Definition
|
|
Term
| How quickly are routine testing results available? |
|
Definition
|
|
Term
| When can lab results take days to weeks? |
|
Definition
| if samples need to be sent out for testing |
|
|
Term
| How is the reference range of a metabolite determined? |
|
Definition
testing a large number of "normal" subjects (not known to have disease) grouped by age & sex
The range is determined by ± 2 standard deviations from the mean |
|
|
Term
|
Definition
| lab results indicitive of need from prompt clinical intervention |
|
|
Term
| What is the protocol when a critical lab value is noticed by the lab technician? |
|
Definition
1) verify value by repeating test
2) immediately notify ordering physician/nurse
3) document notification |
|
|
Term
|
Definition
| true positive will test positive |
|
|
Term
|
Definition
true positive/ (true positive + false negative)
(B/c TP + FN = patients with disease) |
|
|
Term
|
Definition
| true negatives will test negative |
|
|
Term
|
Definition
true negative/ (true negative + false positive)
TN + FP = patients w/o disease |
|
|
Term
| When should sensitivity be maximized? |
|
Definition
| serious but curable disease |
|
|
Term
| When should specificity be maximized? |
|
Definition
| serious, but incurable (since if false negative, it won't change your outcome) |
|
|
Term
Function
positive predictive value |
|
Definition
| determines the likelihood that someone with a positive test has the disease |
|
|
Term
Equation
postivie predictive value |
|
Definition
= true positive/ (true positive + false positive)
TP + FP = total positives |
|
|
Term
| What is the purpose of tests? |
|
Definition
| to reduce clinical uncertainty |
|
|
Term
| What type of test is needed to rule out a disorder? |
|
Definition
| very sensitive therefore negative = negative |
|
|
Term
| What type of test should be used to confirm a Dx? |
|
Definition
| specific therefore positive = positive |
|
|
Term
| Does a single test lead to a Dx? |
|
Definition
| No, at least 1 more test should be done to confirm any Dx |
|
|
Term
| When is an abnormal result more likely to indicate an actual abnormal result? |
|
Definition
| the further it is from the normal range |
|
|
Term
| When can a result in the normal range be considered abnormal? |
|
Definition
| when different from the patient's baseline |
|
|
Term
| When should lab tests be ordered? |
|
Definition
only if likely to help in:
Dx
management
prognosis |
|
|
Term
| How often should tests be done to follow progress of a disorder? |
|
Definition
| depends on the dynamics of the analyte you're testing and the treatment |
|
|
Term
| What is the most common source of errors in results? |
|
Definition
pre-analytical errors:
incorrect draw
incorrect patient
mislabeling of specimen |
|
|
Term
| What happens if the lab instruments give an erroneous result? |
|
Definition
1) try to correct
2) obvious there was an issue with the smear |
|
|
Term
|
Definition
automatic comparison of a sample to the patient's previous samples to avoid random analytical errors
if delta check fails, test automatically re-ran |
|
|
Term
| What is the concern when multiple lab tests are repeatedly requested? |
|
Definition
|
|
