RECALLS page 35-55 Flashcards
(310 cards)
1
Q
Why do we add Coombs control cells to a negative DAT/IAT?
A
To confirm AHG is added.
2
Q
What is the result of using under-washed cells for IAT?
A
False negative result.
3
Q
What should be done with platelets received on ice?
A
Discard and record inventory.
4
Q
A patient has a history of antibodies but a current negative antibody screen. What antibody does she most likely have?
A
Anti-Jka.
5
Q
In the Kleihauer-Betke test, whose blood is being tested for fetal hemorrhage?
A
Maternal blood.
6
Q
What is the optimum temperature for Rh antibodies?
A
37°C.
7
Q
In which cases should a weak D test be performed?
A
Rh-negative donor and Rh-positive baby of Rh-negative mother.
8
Q
In a precipitation reaction, what does antigen excess cause?
A
Postzone.
9
Q
A D+C+E+c+e+ phenotype suggests what possible genotype?
A
R1r″ or R1R2.
10
Q
A D+C−E+c+e+ phenotype suggests what possible genotype?
A
R2r.
11
Q
What differentiates IgM from IgG antibodies?
A
Temperature.
12
Q
What should be done when anti-M is suspected?
A
Acidify the specimen.
13
Q
A mother is R2r and the father is rr. What antibody will the mother produce against the baby?
A
None.
14
Q
When should antigen typing not be performed?
A
If the patient has been transfused within the past 3 months.
15
Q
A patient has a negative antibody screen but a history of anti-K. What is the next step?
A
Perform an IAT crossmatch.
16
Q
What should be done if the blood bank automatic cell washer is not working?
A
Wash manually.
17
Q
Anti-Lea is detected at 28 weeks of gestation. What should be done?
A
Phenotype the father.
18
Q
A patient had fever, nausea, and low WBCs after transfusion. What type of cells should be issued next time?
A
Irradiated cells.
19
Q
A heavy red cell suspension would yield a false negative IAT due to what reason?
A
Too many antigens due to having many RBCs.
20
Q
What is it called when there’s antigen excess in a reaction?
A
Postzone.
21
Q
Which person requires RhIg?
A
Nonsensitized mother.
22
Q
What is the phenotype control for −P antigen?
A
Weakest expression / heterozygous.
23
Q
What is the proper storage condition for bovine albumin?
A
4°C.
24
Q
Anti-A antisera forms a reaction with A1 blood type but not with A2. What should you do next?
A
Remove reagent anti-A from that lot.
25
Anti-A antisera formed a reaction with A1 blood type but not with A2. What should be done next?
Discard the antisera.
26
Anti-Lea is detected in a pregnant woman. What should be done?
Report to physician.
27
Anti-D is present and titer is 32, previously it was negative. What is the next step?
Call the physician and send preliminary report.
28
What is true about Jka antibody?
It is enhanced by enzymes and associated with delayed hemolytic transfusion reactions (DHTR).
29
Which condition is not suitable for quality control?
More concentrated cell used.
30
What should be done if Coombs control cells do not agglutinate in the final phase of the AHG test?
Repeat the test.
31
Coombs test is negative. What should be done next?
Document and retest.
32
A patient has anti-S but their red cells are S antigen positive. What is the probable cause?
Positive DAT (autoantibody coating the cells).
33
A sample is received in the transfusion lab with a spelling error. What should be done?
Request a new sample.
34
What can you not do in a patient who has had a transfusion in the past 3 months?
Antigen phenotyping.
35
What is the next step when an unopened unit of red blood cells is returned unused?
Discard the unit.
36
An Rh-negative mother is pregnant with her second baby, and anti-D is present. What should be done?
Investigate further for immune anti-D and manage accordingly.
37
What is the term for a blood sample that agglutinates with most or all reagents?
Polyagglutination.
38
What tests are performed on cord blood?
ABO, Rh, and DAT.
39
What is a probable reason for a negative DAT after a transfusion reaction?
Donor RBCs have been cleared from circulation.
40
A pregnant patient has anti-D with a titer of 32. What should be done next?
Call the doctor.
41
A patient is not eligible for computer crossmatch but needs blood. What is the next step?
Perform serological crossmatch.
42
A patient experiences shock and diffuse hemorrhage after a blood transfusion. What may be the cause?
Transfusion reaction.
43
No agglutination occurred after adding Coombs reagent. What should be done next?
Repeat the test.
44
Which antibody will not be detected when using papain treatment?
Anti-S.
45
What blood type is required for exchange transfusion?
O negative.
46
In what condition is irradiated blood typically used?
Graft-versus-host reaction (GVHR) prevention.
47
To confirm compatibility: A patient has anti-K, anti-Fya, and anti-M. What phenotype should donor RBCs be?
K-negative, Fya-negative, M-positive.
48
Which ABO blood group has the highest amount of immune hemagglutinins (IH)?
Group O.
49
What is the potential issue if IAT incubation is prolonged to 60 minutes?
False positive due to denatured antibodies.
50
A DAT-positive newborn has what likely antibodies involved?
Anti-D and Anti-Le.
51
A latex agglutination test shows no reaction with positive and negative controls. What is the appropriate action?
Repeat the positive control.
52
Which condition would permanently defer someone from donating blood?
(Specific example not listed; permanent deferral may include conditions like hepatitis, HIV, or high-risk behavior).
53
A unit of cryoprecipitate is thawed and left at room temperature for 2 hours. What should be done?
Reject the unit.
54
Who should receive RhIG?
A woman undergoing amniocentesis at 26 weeks.
55
How often should blood storage refrigerator temperatures be checked in a transfusion service?
Constant monitoring (with recording at least every 4–8 hours depending on policy; “every 8 hours” is often the minimum requirement).
56
What is the storage temperature and duration for thawed frozen plasma (AFFP) prepared with ACD-A?
1–6°C for 5 days.
57
What anticoagulant is used in Cryosupernatant plasma prepared from AFFP?
Sodium citrate.
58
What is the frozen shelf life of Cryosupernatant plasma?
1 year.
59
After thawing, how long is Cryosupernatant plasma valid for transfusion?
Within 24 hours at 1–6°C.
60
What is the storage condition and transfusion limit for thawed Cryoprecipitate?
Store at 20–24°C and transfuse within 4 hours.
61
At what temperature should pooled leukoreduced platelets be stored?
20–24°C with continuous agitation.
62
What is the shelf life of pooled leukoreduced platelets?
7 days.
63
During transport, for how long can agitation stop in apheresis platelets?
Up to 24 hours.
64
What is the storage temperature range for red blood cells stored in SAGM?
1–6°C.
65
What is the shelf life of red blood cells stored in SAGM?
42 days (unless otherwise specified).
66
How long is a red blood cell unit valid after the seal is breached and stored at 1–6°C?
24 hours.
67
How long is a red blood cell unit valid after the seal is breached and stored above 6°C?
4 hours.
68
What is the volume and anticoagulant content of a typical whole blood unit used to prepare RBCs?
480 mL of whole blood with 70 mL of CPD.
69
What does the abbreviation CPD stand for?
Citrate Phosphate Dextrose.
70
What does ACD or ACD-A stand for?
Acid Citrate Dextrose / Acid Citrate Dextrose Solution A.
71
What does LR stand for in blood component labeling?
Leukoreduced.
72
What does SAGM stand for?
Saline, Adenine, Glucose, Mannitol.
73
Where is information related to chemical hazards found?
Material Safety Data Sheets (MSDS).
74
What is the most important step in the proper handling of any hazardous substance?
Use of personal protective equipment.
75
What should be done if an MLT’s gloves become bloody while cleaning up a spill?
Immediately remove gloves and wash hands.
76
To avoid needle sticks, what procedure should always be followed?
Place contaminated sharps into appropriate puncture-resistant, leak-proof container immediately after use.
77
Which of the following leukemias may be morphologically similar to microgranular acute promyelocytic leukemia?
Acute monocytic leukemia.
78
Which of the following conditions may be associated with increased phagocytes?
Septicemia.
79
What peak is the base peak in the given mass spectrum?
The base peak is the tallest peak, which represents the ion of highest relative abundance. Based on the spectrum described, m/z = 43 is the base peak.
80
In PCR with 20 cycles and no product, what should be done?
Increase to 45 cycles.
81
In PCR with 25 cycles and no product, what should be done?
Increase to 45 cycles.
82
In PCR with 30 cycles and no product, what should be done?
Stop and report as negative.
83
What is the role of Uracil DNA glycosylase (UDG)?
Decontamination of carryover contamination in PCR.
84
Why did DNA fail to hybridize in a PCR reaction?
Reverse primer was not used.
85
Two PCR products have different melting points. What does the higher melting point indicate?
The product has more G-C bonds.
86
You isolate gram-positive rods that are non-motile, non-hemolytic, aerobic, and boxcar-shaped. What is the most likely organism?
Bacillus anthracis.
87
What is the correct method when culturing a urine specimen?
Use a 0.01 mL calibrated loop and insert diagonally.
88
A non-hemolytic, slide coagulase-negative Staphylococcus is isolated from a female urine specimen. What should be done next?
Perform tube coagulase test.
89
An oxacillin sensitivity test for Streptococcus pneumoniae shows a 20 mm zone after 16 hours. What is the next step?
Incubate for 4 more hours (total of 20–24 hours).
90
What is the best stain for acid-fast bacteria?
Ziehl–Neelsen (ZN) stain.
91
What is the purpose of Masson Trichrome stain?
To differentiate between collagen and smooth muscle in connective tissue.
92
What pigment is demonstrated by the Masson Fontana stain?
Melanin.
93
What is the Verhoeff’s van Gieson (VVG) stain used for?
To demonstrate elastic fibers in connective tissue.
94
What is the difference in appearance between VVG and Gomori’s Aldehyde Fuchsin (GAF) stain for elastic fibers?
VVG stains elastic fibers black, while GAF stains them royal purple.
95
What does the Gordon & Sweet Reticulin stain demonstrate?
Reticulin fibers in connective tissue.
96
What does the Periodic Acid Schiff (PAS) stain demonstrate?
Glycogen, neutral polysaccharides, basement membrane, and fungi.
97
What does Alcian Blue stain demonstrate, and how does pH affect it?
Acidic mucins and glycoproteins. At pH 1.0 it shows sulfated mucosubstances, and at pH 2.0 it shows acid mucopolysaccharides.
98
What does Mucicarmine stain demonstrate?
Carboxylated and sulfated mucins and the mucopolysaccharide capsules of Cryptococcus neoformans.
99
What is Congo Red stain used to demonstrate?
Amyloid.
100
What is Oil Red O stain used for, and what is an important handling note?
It demonstrates neutral lipids (fat stain) and xylene must not be used.
101
What is the difference between Gram stain and Gram-Twort?
Gram-Twort includes an additional counterstain (Twort solution) that stains cytoplasm and collagen.
102
What does the Ziehl-Neelsen stain demonstrate?
Acid-fast bacteria, such as Mycobacterium tuberculosis.
103
What is Grocott’s Methenamine Silver (GMS) stain used for?
To demonstrate fungal hyphae and spores by targeting mucopolysaccharides in fungal cell walls.
104
What is Warthin-Starry stain used to detect?
Helicobacter pylori.
105
What pigment is demonstrated by Schmorl’s stain?
Melanin.
106
What is Perl’s Prussian Blue stain used for?
To demonstrate ferric iron (hemosiderin).
107
What are the CLSI-recommended incubation conditions for Streptococcus pneumoniae Kirby-Bauer testing?
• Medium: Mueller-Hinton with 5% sheep blood
• Temperature: 35°C ± 2°C
• Atmosphere: 5% CO₂
• Duration: 20–24 hours
108
What are the incubation conditions for beta-hemolytic streptococci in Kirby-Bauer testing?
Same as for Streptococcus pneumoniae:
• MHA with 5% sheep blood
• 35°C ± 2°C
• 5% CO₂
• 20–24 hours
109
What are the recommended Kirby-Bauer incubation conditions for Enterobacteriaceae and other non-fastidious gram-negative bacilli?
• Medium: Mueller-Hinton plain agar
• Temperature: 35°C ± 2°C
• Atmosphere: Ambient air
• Disk diffusion: 16–18 hours
• Dilution method: 16–20 hours
110
What are the incubation conditions for Staphylococcus spp. in disk diffusion?
• Medium: Mueller-Hinton plain
• Temperature: 35°C ± 2°C
• Atmosphere: Ambient air
• Duration: 16–18 hours
111
What are the incubation conditions for Enterococcus spp. in susceptibility testing?
• Same as for Staphylococcus spp. and Enterobacteriaceae
• Medium: Mueller-Hinton plain
• Temperature: 35°C ± 2°C
• Atmosphere: Ambient air
• Specific note: All vancomycin susceptibility methods require 24-hour incubation.
112
When should you stop flushing your eyes after a splash of acid?
After 15 minutes.
113
Which type of PPE provides the best protection against airborne diseases?
N95 face mask.
114
What type of fume hood is most commonly used in a hospital laboratory?
Biosafety Cabinet (BSC) Class II.
115
Where should an emergency eye wash station be located?
Within 10 seconds walking distance of the eye hazard.
116
Which of the following crystals may be found in normal alkaline urine?
b) Triple phosphate
117
Which organism will most likely cause impetigo?
b) Streptococcus pyogenes
118
Which organism can be used as the negative control for the PYR test?
c) Streptococcus agalactiae
119
Stool cultures for Campylobacter are incubated at which temperature?
c) 42°C (Note: this is a corrected and standard answer for Campylobacter incubation)
120
Heinz bodies are:
Denatured hemoglobin
121
Stain used to demonstrate Heinz body inclusions:
New methylene blue
122
Coffin-lid shaped crystals in urine indicate the presence of:
Triple phosphate
123
What is the growing condition for Bacteroides fragilis?
Anaerobic
124
Nonspecific esterase stain is used to differentiate which cell types?
Myelocytes from monocytes
125
A shift to the left in the RBC histogram is indicative of:
Microcytic anemia
126
Where should glacial acetic acid be stored?
In a low-gravity (low-level) flammable chemical cabinet or fume hood
127
What should you do if the barcode scanner is not working?
Reboot the scanner
128
What is the required blood volume to prepare 750 mL of 5% blood agar?
37.5 mL
129
What should be done if tubes break in the centrifuge?
Wait 30 minutes before opening the lid
130
Specimens that require a Staphylococcus streak for culture include:
BAL (bronchoalveolar lavage) or conjunctival swab
131
Why do we add Coombs control cells to all negative IAT/DAT tests?
To confirm that AHG was added and the test is valid
132
What does a shift in quality control data indicate?
A sudden change in instrument calibration or reagent performance
133
What does a trend in QC data usually suggest?
A gradual deterioration of reagents or instrument performance
134
What information is needed to calculate standard deviation (SD)?
Coefficient of variation (CV%) and the mean
Formula: SD = (CV × mean) ÷ 100
135
Westgard rule: A single QC value beyond ±3SD indicates?
Rejection of the run; investigate before reporting results
136
Westgard rule: Two consecutive values beyond ±2SD on the same side suggest?
A systematic error; apply 2-2S rule
137
What is the calculation for anion gap?
Na⁺ – (Cl⁻ + HCO₃⁻)
138
What is the formula for osmolal gap?
Measured osmolality – Calculated osmolality
Calculated osmolality = (2 × Na⁺) + (glucose / 18) + (BUN / 2.8)
139
Which test results require interpretation of PT and APTT?
Coagulation testing to evaluate clotting disorders or monitor anticoagulant therapy
140
Which leukemia is associated with CD33+ and CD10–?
Acute Myeloid Leukemia (AML)
141
Which leukemia is associated with CD10+ and CD33–?
Acute Lymphoblastic Leukemia (ALL)
142
Which leukemia shows CD5+ marker?
Chronic Lymphocytic Leukemia (CLL)
143
Which leukemia shows CD19+ marker?
B-cell lineage leukemias, especially B-cell ALL and CLL
144
What is an additional precaution when handling Bacillus anthracis?
Inform the receiving laboratory and use primary and secondary containment
145
What are media characteristics of Bacillus anthracis?
Non-hemolytic, “Medusa head” colonies, non-motile, grows on blood agar
146
What is a typical feature of an atypical lymphocyte?
Low nucleus-to-cytoplasm (N:C) ratio
147
Which specimen requires a Staphylococcus streak for culture?
Bronchoalveolar lavage (BAL)
148
Which cell has the least forward scatter in flow cytometry?
Nucleated red blood cell (NRBC)
149
Which cell has the most forward scatter in flow cytometry?
Monocyte
150
PCR amplification occurred but no detection. What is the most likely cause?
Incorrect probe
151
What anticoagulant is used for synovial fluid, and how should it be stored if delayed?
Heparin; store at 4°C
152
Antibiotics were stored in a freezer, but the temperature rose to 2°C. What should you do?
Document and use for 1 day
153
ABO discrepancy: Anti-A 3+, Anti-B 3+, Rh Control 0, A1 cells 3+, O cells 0. What’s the next step?
Consider A2 with anti-A1; confirm with additional testing or lectin
154
What enhances nuclear staining in histology?
Prolonged hematoxylin staining
155
What is the purpose of the anti-roll plate in cryostat sectioning?
To flatten the section and prevent curling
156
A baby has HDN, but mother and baby share the same ABO group. What is the likely cause?
Antibody to low-frequency antigen
157
Which specimen should be processed first?
CSF (followed by blood culture and arterial blood gas)
158
Klebsiella shows hazy growth within the zone of inhibition on cephalosporin susceptibility testing. What is the next step?
Ignore swarming and measure the zone of inhibition as normal
159
Given the following reaction: Screening Cell 1 = 2+, Screening Cell 2 = 0, what is the likely antibody?
Anti-M
160
What lab findings are expected in hemolytic anemia?
Decreased hemoglobin and decreased haptoglobin
161
What causes an increased beta region in serum protein electrophoresis?
Ceruloplasmin
162
What can cause no banding in DNA electrophoresis?
No electrical current or incorrect pH
163
What electrolyte pattern is seen in hyperparathyroidism?
Increased calcium, decreased phosphate
164
Is pH directly proportional to HCO₃⁻ and inversely proportional to H₂CO₃?
True
165
What causes increased polychromasia on a peripheral smear?
Bone marrow response to untreated iron-deficiency anemia (IDA)
166
What does a blue anaerobic indicator mean?
Anaerobic conditions are not met; oxidation is present.
167
Which types of calculations are important in lab math?
RBC indices, corrected WBC count, CV, SD, creatinine clearance, calculated osmolality, LDL calculation, and anion gap.
168
What substance can cause a markedly depressed freezing point in measured osmolality?
Ethanol.
169
What is an advantage of indirect over direct ion-selective electrode (ISE)?
Indirect ISE is more automated and allows high throughput but is affected by high protein/lipid levels.
170
What should be studied regarding 24-hour urine collection?
Proper collection techniques and appropriate preservatives.
171
How should critical high or low limits be handled?
Validate and promptly report to the physician or appropriate caregiver.
172
Which storage device loses data when the system power is off?
RAM (Random Access Memory).
173
What is a critical specimen for orientation during embedding?
Small intestine or colon (due to layered structures).
174
What causes turbidity in alkaline urine that disappears on heating?
Amorphous phosphates.
175
Which urinary cast is considered insignificant?
Hyaline cast.
176
What does non-specific esterase stain help differentiate?
Monoblasts from myeloblasts.
177
What lab values are typically elevated in polycythemia vera?
RBC, WBC, platelet count are all elevated; ESR is decreased.
178
Amorphous basophilic material in H&E staining is likely:
Calcium.
179
What is the best medium to perform the indole test?
5% Sheep Blood Agar (SBA).
180
What does a 20 mm zone of inhibition in the optochin test suggest for S. pneumoniae?
Sensitive; confirm after 20–24 hours and with bile solubility.
181
What is the best antibiotic for E. coli isolated from CSF?
Ceftriaxone.
182
Which antibiotic is used for Staphylococcus aureus isolated from blood culture?
Vancomycin.
183
What stain helps differentiate bacteria from dust?
Acridine orange.
184
What should you do next if slide coagulase is negative?
Perform tube coagulase.
185
An organism is catalase positive, slide coagulase positive, and tube coagulase negative. What is it likely to be?
Staphylococcus lugdunensis or other Staphylococcus sp. (not S. aureus).
186
What biosafety cabinet is best for sputum preparation?
BSC Class II.
187
What should you do if a blood culture is positive?
Call the physician and report results.
188
An optochin-resistant, bile soluble, mucoid colony was found. What should be done?
Confirm with repeat bile solubility test; report Streptococcus pneumoniae if positive.
189
What is the likely organism in a human bite wound infection, and what are its characteristics?
Eikenella corrodens—gram-negative, non-lactose fermenter.
190
A zone of inhibition is measured for S. pneumoniae after 16 hours. What is the next step?
Continue incubation to 20–24 hours.
191
What color do acid-fast bacilli stain?
Red.
192
What is the most likely reason for a negative blood culture in a suspected case of septicemia?
Inadequate blood volume collected.
193
How do you calculate urine colony count?
Colonies × dilution factor × 100 (if 0.01 mL loop used).
194
What should be done after swelling is noted at a phlebotomy site?
Apply pressure for 2 minutes, bandage the site.
195
What lab findings are typical in Disseminated Intravascular Coagulation (DIC)?
Prolonged PT and APTT, elevated FDP, and D-dimers.
196
How do you differentiate hereditary from acquired hemolytic anemia?
Perform Direct Antiglobulin Test (DAT).
197
What topics fall under professionalism and ethics in lab practice?
Proper communication, confidentiality, integrity, informed consent.
198
How long is a blood culture incubated in an automated machine?
5 days, up to 14 days if clinically indicated.
199
What is the anticoagulant used in blood culture bottles?
SPS (Sodium polyanethol sulfonate).
200
What is the function of a modem?
Data transmission.
201
What is the primary function of a regulatory body?
To protect the public.
202
What is the best method for confidential delivery of lab results?
Facsimile (fax).
203
What is the best method for blood disposal?
Commercial method (e.g., 5.25% sodium hypochlorite or autoclaving for 15 minutes).
204
What is the best antiseptic for blood collection in alcohol testing?
Soap and water.
205
How are interfering substances best avoided in creatinine determination?
By using kinetic methods (to avoid interference).
206
What should be done if acid is spilled on the body?
Rinse with copious amounts of water.
207
What should be done if acid is spilled on the floor?
Use an acid neutralization kit.
208
What should you do if dry picric acid powder is seen outside the bottle?
Call the safety/disposal team immediately.
209
What extinguisher should be used for electrical equipment on fire?
CO₂ extinguisher.
210
What is the safest method for opening a blood tube?
In a biological safety cabinet.
211
What should you do if PCR product is not detected colorimetrically after 20 cycles?
Increase to 45 cycles.
212
What should you do if PCR product is not detected after 30 cycles?
Report as negative.
213
What is the effect of higher G+C content on DNA melting point?
Increases melting point.
214
In which type of software is data retrieval easiest?
Spreadsheet software.
215
If a dialysis center is opened in the community, which test volumes are likely to increase?
Hematology and biochemistry.
216
What is the best venipuncture method for a 3-day-old neonate?
Heel puncture using an EDTA microtainer.
217
What is the next step if swelling occurs while drawing blood?
Apply direct pressure for 2 minutes, then bandage; advise patient to continue applying pressure.
218
A properly labeled tube for LDH test is brought by another healthcare professional. What should you do?
Enter the specimen into the LIS.
219
What is the best communication method when your colleague has a language barrier?
Use diagrams to explain.
220
A new test you’re unfamiliar with is requested. What is your next step?
Discuss the situation with your supervisor.
221
An MLT makes a mistake. What should be done?
Acknowledge and report the error to the supervisor immediately.
222
An otherwise calm and friendly MLT becomes suddenly angry. What should you do?
Speak calmly with them, and try to understand or de-escalate the situation.
223
An MLT appears frustrated with work circumstances. What should you do?
Try to motivate and support them.
224
What hazard symbol classes were covered in safety training?
Classes include flammable, corrosive, toxic, biohazard, radioactive, etc. (Referenced in WHMIS/GHS training).
225
A manager announces that all staff must share night shifts. What is the best reaction?
Accept it.
226
The lab is moving from 8-hour to 12-hour shifts. What is the best response?
Consider the benefits of 12-hour shifts.
227
To protect patient privacy in the LIS system, what feature is used?
Username and password.
228
Which laboratory discipline requires 100% accuracy in proficiency testing?
Transfusion.
229
What is a major benefit of using a Laboratory Information System (LIS)?
Reduces workload.
230
You are asked to perform a task you’re not trained for. What should you do?
Express your lack of competency.
231
A patient previously known as A Rh-positive now shows an ABO discrepancy. A1 cells show 1+ and rouleaux is seen microscopically. What is the next step?
Perform saline replacement.
232
A patient phenotype is DC+C+E+c+e+. What is the most likely genotype?
R1R2.
233
You are picking up a unit of blood and notice brown patches in the bag. What should you do?
Remove it from inventory.
234
A pregnant woman at 28 weeks is found to have anti-M. What is the next step?
Phenotype the father.
235
A pregnant woman at 28 weeks is found to have anti-Jka. What is the next step?
Titer the antibody and re-titer every 4 weeks until delivery.
236
You’re performing a DAT on a STAT sample and the cell washer is not functioning. What should you do?
Wash the cells manually and fix the cell washer later.
237
An antibody screen shows a 1+ reaction. What should you do next?
Add more plasma to enhance the reaction.
238
On H&E stained slides, eosin appears pale. What could be the cause?
Ammonia water was not rinsed enough.
239
An amorphous brown pigment on H&E stained slides could be demonstrated by which stain?
Perl’s Prussian Blue (PPB).
240
Some patches of tissue on a slide remain unstained. What is the likely cause?
Insufficient waxing during embedding.
241
Which of the following acid–base disorders is true when pH is low, HCO₃⁻ is low, and pCO₂ is normal?
a) Metabolic acidosis
242
A blood gas syringe arrives with patient name, date of birth, tests ordered, and 'arterial blood' noted—but no time of draw. What should you do next?
Ask the floor to provide the time of draw (arterial blood is irretrievable; you must document or redraw if information is missing).
243
A physician calls questioning a lab result. What is your first step?
Repeat the test before discussing results.
244
You know hemolysis can falsely increase potassium. What should you do if a plasma/serum specimen is grossly hemolyzed?
Reject the specimen.
245
A patient’s coagulation panel shows: PT = 17.45 s (↑), aPTT = 37 s (normal), Thrombin Time = ↑. Which anticoagulant is most likely?
Unfractionated heparin (prolongs TT more than PT/aPTT).
246
Which is the best practice when opening a potentially airborne biohazard specimen?
Open it inside a Class II biosafety cabinet.
247
A Kirby–Bauer plate for Streptococcus pneumoniae shows 'susceptible' at 14 hours. What do you do?
Continue incubating to the full 20–24 hours before final interpretation.
248
What information is mandatory on the requisition to perform Clostridioides difficile toxin testing?
Patient’s diagnosis and/or date of admission.
249
The antibiotic disc freezer reads –10 °C in the morning. What should you do with the discs?
Use them—because they remained frozen overnight, they are still within acceptable storage.
250
How much blood is needed to prepare 750 mL of blood agar?
37.5 mL
251
What does a blue indicator after 48 hours in a candle jar suggest?
Leak in the gasket
252
How do you inactivate complement in serum samples?
Heat at 56°C for 30 minutes
253
What type of urine is associated with triple phosphate crystals?
Alkaline urine
254
What is required to compute corrected WBC count in the presence of nucleated red cells?
Corrected WBC = (WBC × 100) / (NRBC + 100)
255
What is the correct PPE donning sequence?
Gown → Mask → Goggles/Safety Glasses → Gloves
256
Tube coagulase positive organism is?
Staphylococcus aureus
257
What can complicate communication in the lab?
Use of jargon
258
Which organism is commonly associated with cystic fibrosis and burn patients?
Pseudomonas aeruginosa
259
Why might gram-negative coccobacilli appear gram-positive?
Improper decolorization
260
What is an example of negligence in lab practice?
Releasing results without running quality control
261
What is the first step if Bacillus anthracis is suspected?
Notify the physician and appropriate authorities immediately
262
What are the calcium and phosphate levels in hyperthyroidism?
Increased calcium, decreased phosphate
263
What is the next step if sickle cells are seen in a smear?
Perform hemoglobin electrophoresis
264
What to do if the cell washer is not working?
Wash cells manually
265
When should you refuse to collect a sample from a patient?
If the patient is aggressive or poses a safety risk
266
What happens if anti-roll plate is not used in cryostat sectioning?
The tissue section curls
267
Sensitivity discs were stored at –35°C, but temperature rose to –20°C. What should be done?
Discard the discs
268
What type of loop can cause a false positive oxidase test?
Nichrome (use platinum loop instead)
269
PCR yields no result—what is the likely issue?
Incorrect primer used
270
You are assigned a new shift. What should you do?
Discuss the benefits and your availability
271
Proficiency results from your lab are 900, others report 98. What should you do?
Investigate and calculate the error
272
Prolonged aPTT is associated with deficiency in which factor?
Factor VIII
273
Patient with Hemophilia A has massive bleeding. What is the treatment?
Recombinant Factor VIII
274
What is a disadvantage of point-of-care testing (POCT)?
High cost
275
Auer rods are seen in which leukemia?
Acute Myeloid Leukemia (AML)
276
Increased aPTT without heparin therapy indicates?
Lupus anticoagulant
277
Which tests take priority in STAT processing?
ABG, electrolytes, creatinine, urine C&S
278
What is required to compute anion gap?
Anion gap = Na⁺ – (Cl⁻ + HCO₃⁻)
279
What lab result helps differentiate primary from secondary fibrinolysis?
D-dimer (positive in secondary fibrinolysis, e.g., DIC)
280
Howell-Jolly bodies are remnants of what?
DNA
281
What to do if a centrifuge tube breaks?
Turn off, wait 30 minutes, then disinfect
282
How to handle a spill of flammable and corrosive liquids?
Turn off ignition source immediately
283
CSF glucose is 3 mmol/L and blood glucose is 5 mmol/L. What is the interpretation?
Normal CSF-to-blood glucose ratio (typically ~60%)
284
What is considered a breach of confidentiality?
Discussing patient results in public areas
285
When should antigen phenotyping NOT be performed?
If the patient was transfused within the last 3 months
286
Common cause of subacute bacterial endocarditis?
Viridans group streptococci
287
What should be done with platelets received on ice?
Discard them
288
Green staining in Masson’s Trichrome may indicate what?
Improper use of phosphomolybdic acid
289
If the blood culture incubator fails, what is the alternative?
Incubate manually at appropriate conditions
290
What are examples of systematic error indicators in QC charts?
Trends and shifts
291
What should you do with a control reading of 125?
Depends on acceptable range—if outside, reject and repeat
292
What is the formula to compute the bicarbonate to carbonic acid ratio?
HCO₃⁻ to H₂CO₃ ratio = 20:1 (Normal acid-base ratio)
293
A patient is visibly nervous before venipuncture. What should you do?
Show professionalism and reassure the patient calmly
294
What is the effect of an increased volume of leukemic patients in a facility?
Increased workload in the blood bank
295
What is the minimum Gray (Gy) dose required for irradiated blood products?
25 Gy
296
What should be adjusted if a black area appears while attempting Kohler illumination?
Adjust the centering screws
297
High platelet count by analyzer but low count manually may suggest what condition?
DIC or essential thrombocythemia
298
What is the maximum recommended number of blood culture sets within 24 hours?
2 sets or fewer than 3
299
In DNA electrophoresis at pH 7.8, in which direction will DNA migrate?
Toward the anode (positive end)
300
What is the phenotype control used for P antigen testing?
Heterozygous or weakest expression
301
What to do if Staphylococcus aureus shows negative tube coagulase at 37°C after 24 hours?
Reincubate at 22°C for another 24 hours
302
Methylene blue strip in an anaerobic jar is still blue despite warmth and condensation. What is the issue?
Broken gasket or expired indicator strip
303
If H. influenzae with beta-lactamase shows ampicillin susceptibility, how should it be reported?
Report as resistant
304
What should be done in the case of erroneous bacterial catalase controls?
Repeat controls using clinical isolates
305
What method is used for colony counts <1 × 10⁵/mL in urine cultures?
Fluorometry with acridine orange
306
Which condition must be reported immediately to a physician?
Gas gangrene
307
Which specimen type is appropriate for a Staph streak or CAMP test?
CSF, urine, or amniotic fluid (e.g., Group B Streptococcus testing)
308
Which chemical should be stored in a flammable cabinet?
Nitric acid
309
What happens when urine stands for too long at room temperature?
Leukocytes lyse and amorphous crystals may dissolve
310
What should be done with tissue submitted in formalin for culture?
Reject the sample (formalin kills microorganisms)
