| Exam Code/Number: | ASCP-MLTJoin the discussion |
| Exam Name: | MEDICAL LABORATORY TECHNICIAN - MLT(ASCP) |
| Certification: | ASCP |
| Question Number: | 562 |
| Publish Date: | Jul 26, 2026 |
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After collection all blood should be stored at 1 - 6oC, unless it is going to be used as a source of platelets.
A refrigerator used to store whole blood must be able to maintain a temperature in the ranges of:
AABB Standards do not require a DAT, autologous control, or a minor crossmatch for pretransfusion testing.
Essential components of compatibility testing include all of the following except :
A zone of inhibition is the area around an antibiotic-infused paper disk that does not show any bacterial growth. The antibiotic impregnated on the disk will diffuse into the agar in the area surrounding the disk. If the bacteria are sensitive to the antibiotic, they cannot grow near the disk. The size of the zone is proportional to how sensitive the organism is. If the organism is resistant to the antibiotic, it will grow very closely to the disk.
The size of the zone of suppressed growth on a sensitivity plate using sensitivity disks is referred to as the zone of:
Rule-out is a process by which antibodies are identified as being unlikely in a given sample because of the absence of an expected antigen-antibody reaction. In other words, the absence of a reaction is noted with a cell that is positive for the corresponding antigen.
Although rule-out procedures may vary somewhat from institution to institution, the following general principles apply:
Non-reactive cells are selected for rule-out. To be classified as non-reactive, a cell must NOT have reacted at any phase of testing in a given panel or screen.
Using the logic that if the rule-out cell is positive for a given antigen, it should have reacted with the corresponding antibody, you can rule-out antibodies that correspond to antigen positive cells.
To increase the probability that rule-out will not mistakenly eliminate a weakly-reacting antibody that exhibits dosage*, use only cells that are homozygous for the corresponding antigen for those systems that generally show dosage. Generally these include: C, c, E, e, Fya, Fyb, Jka, Jkb, M, N, S, and s.
In this case, it is only possible to rule out on screening cell 2 since it demonstrates a negative reaction with the patient serum. Anti-C cannot be ruled out since the C antigen is heterozygous on screening cell 2 with c.
Anti-Fya cannot be ruled out since this antigen is not present on screening cell 2. Anti-M and anti-Jka can be ruled out since the antigens are homozyous while demonstrating a negative reaction on screening cell 2.
Rule-out, while very useful, can lead to error. Ruling out an antibody should be combined with other supporting data to increase confidence in the solution; the more data collected, the higher the probability that the final solution is correct.
*Dosage means that there are two "doses" of the same antigen present on the red cells . Antibodies that exhibit dosage react more strongly with homozygous cells (e.g., Jka Jka) than with heterozygous cells (e.g., Jka Jkb) .
Based on the phenotype of the RBC screening cells, and patient results shown on the right, which of the following antibodies CANNOT be ruled out?
The microscopic features shown here represent Scopulariopsis species. In most instances, particularly if a patient does not have underlying immunologic or hematologic disease, Scopulariopsis species should be considered a contaminant when recovered from a sputum specimen. However, if there is clinical or X-ray evidence of mycotic pulmonary infection, additional daily induced sputum specimens should be obtained.
If Scopulariopsis species or any other hyaline mold is recovered from two or more successive specimens, its potential as a pathogenic agent should be considered. Scopulariopsis species have been reported as the agents of pulmonary fungus ball infections in patients with preexistent cavities and as a cause of pneumonia in patients with leukemia.
Invasive pulmonary disease by this agent has not been reported.
The fungus illustrated in this photomicrograph was recovered from an induced sputum specimen from a 74 year old man with chronic obstructive pulmonary disease. This isolate is most likely:
