Free ASCP ASCP-MLT Practice Exam with Questions & Answers

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?

These are tyrosine crystals

Urinalysis & Other Body Fluids

True or false? Cystine crystals are present on this slide.

The term universal precautions refers to:

The DAT, or direct antiglobulin test, is used to detect antibodies coating RBC's in vivo.

The Direct Antiglobulin Test (DAT) is usually used to detect:

Transport media are required for throat culture swabs but not for rapid strep tests.

Most researchers believe that the small size and increased density of LDL molecules found in atherogenic dyslipidemia enable the molecules to more easily invade the endothelium and arterial wall of vessels.

Why are small dense LDL molecules more atherogenic?

This drawing depicts beta thalassemia minor B+/B. In Beta thalassemia minor B+/B, one beta gene locus is partially deleted or inactive.

Hematology

This drawing depicts which beta chain genotype ?

Neutrophils reside in the peripheral circulation for only 7-8 hours ( approx. 7.5 hours) before entering the tissues and body cavities. This process is called diapedesis.

Hematology

How long are healthy neutrophils expected to reside in the peripheral blood of an adult?

Electrophoresis uses an electric field to separate molecules based on differences in net electrical charge. The rate of electrophoretic migration is also dependent on the ionic radius of the molecule, the viscosity of the solution through which it is migrating, the electrical field strength, temperature, and the type of supporting medium used.

Electrophoretic separation fundamentally relies on:

Joint pain is a common early symptom of HH. Cirrhosis of the liver, cardiomyopathy, and diabetes are late symptoms of HH.

What is a common early symptom of hereditary hemochromatosis (HH)?

% concentration (expressed as a proportion or ratio) x volume needed = mass of reagent to use

So... 10% (w/v) solution of sodium hydroxide x 200 mL needed = 20 grams of sodium hydroxide

How many grams of sodium hydroxide are required to prepare a 200 ml solution of a 10% (weight per volume) solution? (Atomic weights: Na = 23; 0 = 16; H = 1)

Flow cytometry employs a combination of fluorescent antibody tagging of cells and analysis with laser light scatter.

What principle(s) of flow cytometry are employed when performing immunophenotyping:

Match each of the following definitions associated with heart disease and heart failure to the term that it defines.

1. Congestive heart failure

2. Infarction

3. Ischemia

4. Angina

Elevation in conjugated bilirubin is most likely to be found in which of the following conditions:

This type of laboratory testing provides immediate assessment of the patient and can be performed at their bedside: