Practice Test Geeks(MLS) Medical Laboratory Scientist Practice Test
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Laboratory Equipment & Techniques Flashcards

7 cards from real MLS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Laboratory Equipment & Techniques flashcards as text

  1. Which type of microscope objective is used for examining oil-immersion preparations and has the highest magnification in routine clinical microscopy?

    Answer: 100× objective (oil immersion)

    The 100× oil-immersion objective requires immersion oil to fill the gap between the objective and slide, maximizing numerical aperture and resolution for detailed morphology.

  2. During capillary blood collection, why should the first drop of blood be wiped away?

    Answer: It may be contaminated with tissue fluid that dilutes the sample

    The first drop may contain interstitial (tissue) fluid from the puncture, which dilutes the blood sample and can alter analyte results.

  3. A laboratory uses a 1:10 dilution of a sample. If the original concentration is 500 mg/dL, what is the concentration in the diluted sample?

    Answer: 50 mg/dL

    A 1:10 dilution reduces the concentration by a factor of 10; 500 mg/dL ÷ 10 = 50 mg/dL in the diluted sample.

  4. Which evacuated tube additive is used in a serum separator tube (SST) to facilitate clot formation and serum separation?

    Answer: Clot activator (silica particles) with gel separator

    SSTs contain silica particles to activate clotting and a polymer gel that migrates during centrifugation to form a barrier between serum and clot.

  5. What is the correct order of draw when collecting multiple evacuated blood tubes via venipuncture?

    Answer: Blood culture → Citrate → SST → Heparin → EDTA

    The CLSI recommended order of draw is: blood culture, citrate (blue), serum/SST (red/gold), heparin (green), EDTA (lavender/purple), then other tubes.

  6. The Beer-Lambert Law states that absorbance is directly proportional to which two variables?

    Answer: Concentration and path length

    Beer-Lambert Law: A = εlc, where absorbance (A) is directly proportional to molar absorptivity (ε), path length (l), and concentration (c).

  7. Which quality control material is used to verify that a laboratory test is performing correctly at a concentration near the medical decision level?

    Answer: Control material (QC)

    Control materials are independent samples with known (or target) values run alongside patient samples to monitor ongoing assay performance.