ClinLab 3: Final Final Review

Question 1

What samples need to be refrigerated if their delivery to the lab is delayed?

Answer 1

Respiratory
Urine
Sputum
Stool

Question 2

What samples need to be maintained at room temps if their delivery to the lab is delayed?

Answer 2

CSF
Body fluids
Blood cultures

Question 3

What criteria will get samples rejected by the lab?

What is the exception?

Answer 3

Improper label or container
Leakage
Unsuitable specimen
Duplicates- unless blood culture for endocarditis
Body fluids need to be delivered stat

Question 4

What infections can kids get from sucking/oral route

Answer 4

Roseola- droplet transmission
Herpes- herpetic whitlow
Giardia
Hep A
Otitis Media

Question 5

Define acute endocarditis

Answer 5

Serious/aggressive septicemic episodes on healthy cardiac valves (catheter) from skin flora, Staph A/MRSA
IVDU- affects tricuspid valves

Question 6

Define subacute/gradual endocarditis

Answer 6

Occurs in damaged cardiac valves from congenital defects, atherosclerosis, rheumatic fever

Question 7

What microbes can cause subacute/gradual endocarditis

Answer 7

Endogenous oral flora:
Strep Viridians (S mutans/mitis/snaguis/milleri) 
Intestinal flora (S bovis – suggestive of gastric cancer)  
Skin flora: Staph aureus

Question 8

What are the HACEK microbes that commonly cause endocarditis

Answer 8

Haemophilus species
Aggregatibater
Cardiobacterium
Eikenella
Kingella

Question 9

S/Sx of bacteremia, endocarditis and sepsis?

These samples need to be taken prior to ?

Answer 9

Sx: fever, leukocytosis, N/C

Collect before antibiotic therapy

Question 10

Define a Blood Culture Set

Answer 10

1 “set” = 1 aerobic and 1 anaerobic bottle
Different sites/times
No more than 4 total sets w/I 24 hours
Pediatric patients 1 bottle

Question 11

What is the significance of a positive blood culture?

Answer 11

Growth of the same organism in repeated culture: True positive
Growth of different organism in different culture bottles: Contamination, bowel spillage
Growth of normal skin flora – likely contamination w/ Coagulase negative Staph, Coryn, Bacillus, or Propion
Organisms like Viridians Streptococci or Enterococci= possible endocarditis – associated w/ low grade symptoms

Question 12

What must be done after the receipt of blood culture results?

Answer 12

Always match culture results with S/Sx

Question 13

Define Antibiogram

Answer 13

Info obtained from C&S performed in the institution in given time– antibiogram is annual.
Provides % of samples for organism which were sensitive to certain antibiotics

Question 14

What info do Antibiograms not provide?

Answer 14

Organism sensitivity to an Abx based on the site of infection
Organism sensitivity based on location in hospital (ICU vs non-ICU)
Average MIC
Abx killing at various doses/concentrations – trend data

Question 15

What pitfalls come with Antibiograms?

Answer 15

Concentration differences between site of infection and in vitro
Penetration to the site of infection Inactivation of drug at site of infection Declining levels in vivo vs continuous levels in vitro
Rapid development of resistance in vivo vs in vitro
FQ and MRSA
Erythromycin induced clindamycin resistance Inaccurate due to small isolate number

Question 16

What is encompassed in Antibiogram data?

Answer 16

DOC- susceptibility, cost and availability

Question 17

Define Passive Immunity

Answer 17

Resistance based on Abs preformed in another host
Administration of Ab against toxins makes large amounts of antitoxin immediately available to neutralize the toxins or limits viral multiplication
Other forms of passive immunity= IgG passed in pregnancy and IgA passed during breast feeding

Question 18

What is the main advantage of passive immunity?

What are the disadvantages?

Answer 18

Prompt availability of large amounts of Ab;

Disadvantages= short life span of these Abs and possible hypersensitivity reactions if globulins from another species are used

Question 19

What are the immunoglobulin classes and what’s their meanings?

Answer 19

IgM: Current infection
IgG: Current infection, Acute and convalescent, Previous exposure (Vaccinated or old infection)
IgA : (secretory) Celiac disease, hepatitis
IgE: Allergen testing

Question 20

Define Primary and Secondary Immunity?

Answer 20

Primary: IgM binds first, specific IgG binds later, makes more IgG specific for that Ag

Secondary: IgM and IgG (memory) react simultaneously

Question 21

Define Titer

Answer 21

Method of expressing concentration
Employs serial dilution to obtain approximate quantitative information
Corresponds to the highest dilution factor that still yields a positive reading.
Often compares acute vs convalescent

Question 22

What does a 4x increase of a titer mean?

Answer 22

Acute infection

Question 23

What happens if only an acute sample is submitted to the lab?

Answer 23

Cut off value is required

Varies by organism and geography

Question 24

Define Primary Response Titer

Define Secondary Response Titer

Answer 24

Day 5 1:4 titer
Day 12 1:64 titer

Re-exposure Titier: 1:256 titer or even higher

Question 25

S/Sx of Hep A-E infection include ?

Answer 25

``` Abd pain/distension Breast development (males) Dark urine Clay stool Fatigue Low fever Generalized itching Jaundice N/V, weight loss ```

Question 26

What labs are drawn to test for acute hepatitis?

Answer 26

``` IgM anti-HAV IgM anti-HBc HBsAg anti-HCV LFTs- based on screening ```

Question 27

What will PE of PT with acute hepatitis show?

Answer 27

Large/tender liver Fluid in abdomen Yellow skin/eyes

Question 28

What is included in a lab work up for acute hepatitis?

Answer 28

``` U/S Autoimmune blood markers Serologies LFT Biopsy, Paracentesis (if fluid present) ```

Question 29

Characteristics of Hep A

Answer 29

Fecal-oral, high incidence in developing countries with low hygiene standards Self-limited, no chronic liver dz At risk: MSM, IVDU, Pts w/ clotting factor disorders Labs: acute hepatitis A: anti-HAV IgM (+), anti-HAV IgG (+) Resolved hepatitis A: anti-HAV IgG (+)

Question 30

Characteristics of Hep B

Answer 30

Spread by contact w/ blood, semen, vaginal fluids. Vaccine available Shared needles, toothbrushes, razors, nail clippers Acute or chronic. Chronic can be active or inactive “carrier”

Question 31

Characteristics of Chronic Hep B

Answer 31

 Clinical evidence: no Sx required. Chronic infection covers a spectrum from no Sx to cirrhosis Labs: IgM Anti HBc (-) AND HBsAg (+) or HBV DNA (+) or HBeAg (+) OR HBsAg (+) or HBV DNA (+) or HBeAg (+) twice at least 6 months apart (any combination is acceptable) Confirmed case: meets lab criteria alone Presumed: Pt w/ single HBsAg (+) or HBV DNA (+) or HBeAg (+) and does not meet acute case definition

Question 32

Characteristics of Hep C

Answer 32

Blood/Vertical spread (mom to baby) Most develop chronic disease Active infection: Anti-HCV EIA: screening (+), Anti-HCV RIBA: confirmatory (+), qualitative HCV RNA (+) EIA assay (screening) to detect HC-Ab, confirmed by RIBA or HCV RNA Hep C RNA assays measure virus levels (viral load) to measure response to therapy Hep C genotype: 6 of them. Most Americans have genotype 1. 2 and 3 respond to therapy

Question 33

Immunoglobulins in PTs that are susceptible

Answer 33

HBsAG neg anti HBc neg anti HBs neg

Question 34

Immunoglobulins in PTs that are immune from natural infection

Answer 34

HBsAG neg anti HBc pos anti HBs pos

Question 35

Immunoglobulins in PTs that are immune from Hep B vaccination

Answer 35

HBsAG neg anti HBc neg anti HBs pos

Question 36

Immunoglobulins in PTs that are acutely infected

Answer 36

HBsAG pos anti HBc pos anti HBs pos IgM anti-HBc neg

Question 37

Immunoglobulins in PTs that are chronically infected?

Answer 37

HBsAG pos anti HBc pos anti HBs neg IgM anti-HBc neg

Question 38

Characteristics of HBsAg

Answer 38

HBV is in the body of the patient Acute: serology turns negative with development of anti-HBs Chronic: HBsAg is persistently positive

Question 39

Characteristics of anti-HBs

Answer 39

Produced in response to HBsAg Presence indicates either an infection or vaccination Vaccine is essentially HBsAg Anti-HBs hangs around for a long time, decreasing gradually with age

Question 40

Characteristics of HBeAg

Answer 40

Comes from the core of the HBV When the core degrade in the serum, Ag is created and can be detected, although not all Pts will have a detectable HBeAg If HBeAg is (+), it is equivalent to a positive HBcAg marker and shows that the BPV is replicating actively and the patient is infectious

Question 41

Characteristics of Anti-HBe

Answer 41

Body’s immune reaction to HBeAg | Presence indicates HBV replication activities have decreased and the Pt is less infections/not infectious at all

Question 42

Characteristics of HBcAg

Answer 42

Totally degraded in the serum and is not detectable, but a portion survives as HBeAg

Question 43

Characteristics of IgM anti-HBC

Answer 43

FIRST immune response against infection, indicates active infection or flare against natural exposure Immune response matures, this is replaced by IgG anti-HBc Anti-HBc is absent in those who have been vaccinated

Question 44

Define Total Anti-HBc

Answer 44

Made in response to HBcAg, refers to presence of either IgG or IgM and does not discriminate Presence indicates prior or current Hep B infection

Question 45

Characteristics of HBV DNA

Answer 45

Indicates active infection (acute or chronic) Used as a quantitative test to monitor response to therapy, mainly in chronically infected patients “Viral load”

Question 46

What test results show active syphilis

Answer 46

+ non-treponemal test (screening) | + treponemal test (confirmatory)

Question 47

What test results show a false positive RPR

Answer 47

+ non-treponemal test (screening) | - treponemal test (confirmatory)

Question 48

What test result show Spirochete or previous syphilis

Answer 48

- non-treponemal test (screening) | + treponemal test (confirmatory)

Question 49

What can cause bacterial traveler's diarrhea

Answer 49

Salmonella Campylobacter Shigella

Question 50

What can cause viral Traveler's Diarrhea

Answer 50

Rota Noro Enteric adeno Astro

Question 51

What can cause parasitic traveler's diarrhea

Answer 51

``` Giardia Cryptosporidium Cyclospora Isospora Balantidium Entamoeba histolytica ```

Question 52

What causes microbes can cause Traveler's Diarrhea

Answer 52

``` Shigella EIEC, EHEC, EPEC, ETEC Salmonella Campylobacter V Cholera ```

Question 53

What microbe specifically causes Traveler's Diarrhea

Answer 53

ETEC from contaminated food/water | Cramps and watery diarrhea

Question 54

What are the Traveler Infections

Answer 54

``` Typhoid fever Leishmaniasis Yellow fever Dengue fecer Leptospirosis Meningitis ```

Question 55

Upper UTIs include ? | Lower UTI is called ?

Answer 55

Pyelonephritis Cystitis (“traditional” UTI) Urethritis (often STI) Prostatitis

Question 56

What causes Cystitis and what are the two types?

Answer 56

E coli, staph saprophyticus, proteus mirabilis, klebsiella, enterococcus Uncomplicated- Healthy adult women (>12), non-pregnant, no fever/N/G/flank pain dx w/ dipstick UA Complicated- Females w/ comorbidities, ALL males, indwelling foley catheters, urosepsis/hospitalization Dx w/ UA and culture

Question 57

Define Pylonephritis and the S/Sx | How is it diagnosed?

Answer 57

Infection of kidney presenting w/ Fever, N/V, HA and flank pain Dx w/ UA, culture, CBC and chemistry

Question 58

What are some complications that can arise from untreated pyelonephritis?

Answer 58

Perinephric/renal abscess- suspected in PTs not improving on ABX Dx- CT w/ contrast, renal US

Question 59

Characteristics of nephrolithiasis w/ UTI

Answer 59

PTs w/ severe flank pain | Consult w/ urology

Question 60

S/Sx of Protatitis | How is it diagnosed

Answer 60

Sx: pain in perineum, lower abdomen, testicles, penis, and with ejaculation, bladder irritation, bladder outlet obstruction, sometimes blood in semen Dx w/ Hx (fevers/chills/dysuria/malaise/myalgias/pain/cloud urine) Tender prostate on PE. Increased PSA. UA and urine culture Risk factors: Trauma, sexual abstinence, dehydration

Question 61

What causes urethritis?

Answer 61

Chlamydia trachomatis | Neisseria gonorrhea

Question 62

S/Sx of Chlamydia trachomatis urethritis

Answer 62

Frequently asymptomatic in females, but can present w/ dysuria, discharge, or PID Send UA, urine culture (if pyuria seen, but no bacteria, suspect chlamydia) Pelvic exam – send discharge from cervical or urethral site for chlamydia PCR Chlamydia screening is now recommended for all females 25 or under

Question 63

S/Sx of Gonorrhea urethritis

Answer 63

May present w/ dysuria, discharge, PID Send UA, urine culture. Pelvic exam – send discharge samples for gram stain culture, culture, PCR You should always also treat for chlamydia when treating for gonorrhea!

Question 64

How is Gonorrhea urethritis diagnosed and with what specimens?

Answer 64

Specimens: urethral/cervical swab, urethral discharge, urine (first void). Dx urethritis/cervicitis: gram stain. Culture (100% specificity), serology (useful for diagnosis of LGV caused by C. Trichomatis), nucleic acid amplification (can test both GC and Ct simultaneously, very sensitive and specific)

Question 65

What is the most common cause of urethritis in females? | What are the S/Sx and causes of recurring infections?

Answer 65

E coli S saprophyticus in young sexually active females. Cystitis, pyelonephritis. Recurring infections – reinfection pathogens: proteus, pseudomonas, klebsiella, Enterobacter, enterococcus, staphylococcus

Question 66

What is the most common cause of urethritis in males? | What S/Sx are seen on PE for Dx?

Answer 66

Enterobacteriaceae. Very low prevalence. S/Sx: urethritis (sterile culture: discharge, dysuria, frequency), prostatitis (obstructed urine flow: “complicated UTI”) PE: CVA tenderness (pyelonephritis). Urethral discharge (urethritis) Tender prostate (prostatitis)