Clinical Chemistry section 2

_____ should be tested within 4 hours or stored refrigerated/frozen

reject when 1 control measurement in a group exceeds the mean +2sd, and another exceeds the mean –2sd. 

This rule identifies systematic error only and can be applied within a run or across runs.

These types of errors are unpredictable and widen the distribution of values.

žcontrols may be purchased with value ranges for tests of interest 

›Speed of approximately 3000-3500 rpms (centrifugal force) for _______ is necessary to remove cells

allowable error is

The likelihood of a negative test result in patients without disease; it measures how well the test excludes disease

Testing that is used to diagnose disease should detect all positives without giving any false positives.

›Measurement of unknown samples that are sent from an outside agency at set intervals, as a test of competency.

A Gaussian distribution is usually

For a data set that is Gaussian distributed, what's the likelyhood that a data point will be within ±1 SD from the mean?

An initial test that should detect everyone with the disease before they present with symptoms

is the ability to detect small concentrations of the measured analyte

is freedom from interference and cross reactivity, to determine solely the analyte that is being measured

SOP stands for Standard Operating Procedure

refers to everything that affects a patient specimen before it is tested for the analyte.

Advantages of gel tubes do not include:

The test method that provides the best available approximation of a true value.

Due to concentration, the first urine of the morning is optimal for testing.

›Computed values that compare your lab with other labs that are using the same instrument with the same methodology.

This rule identifies unacceptable random error or possibly the beginning of a large systematic error

The range of values for a given analyte in a defined population

____— is concerned with sensitivity, specificity, and closest to the true value

At the manufacturer samples are checked against analytical methods known to be free of interference.

Green Top/PST are used for chemistries and contain:

Serum or plasma should be separated within

Delta checks are particularly helpful in detecting misidentified specimens. 

A test used to verify the results of an initial test. 

žA number that describes the number of standard deviations away from the mean that a result is.

Dark blue tops are used for testing trace elements and this additive within them forms calcium salts:

›In general, a CV of <10% is acceptable, and for low level assays, a CV of <15% is acceptable. 

_____ is reproducibility of results.

The greatest percentage of laboratory errors occurs during this phase:

a gradual but steady change in quality control results

žA statistic that describes the distribution of all values around the mean for a particular group.

Analytical activities include: specimen & reagent preparation, instrument calibrations, and providing the lab report.

QC samples are produced from pooled serum samples. Purchased controls may be assayed or unassayed.

—The clinical chemist is concerned with two aspects of information: Accuracy and Relevance

A reference range can be verified by:

Accurate time and patient compliance are not important factors in collecting urine specimens.

A sudden and sustained change.

The range of specimen concentration that can be accurately measured by a test method

Patient position, diet, pregnancy, and stress levels have no affect on testing results.

Systematic error can be best described as consisting of:

______› evaluate individual test results on the basis of normal variation. 

There are 4 major legitimate reasons for ordering a laboratory test: diagnosis, monitoring, research and screening

Proficiency testing consists of _____ challenges _____ times a year for each test that the laboratory offers. 

are cutoff values that help differentiate the presence of a particular disease from the absence of that disease.

24 hour urine collection reduces diurnal variation

reject when 2 consecutive control observations on the same side of the mean exceed the mean ±2sd limit

The achievement of both precision and accuracy.

refers to those variables that affect patient results in the reporting stage

refers to every step involved in the actual analysis of a laboratory specimen.

žPost-analytical activities do not include:

QC monitors the following aspects of testing: 

The Westgard rules use a combination of decision criteria, to decide whether an analytical run is in or out of control.

This rule warns that random error or systematic error may be present in the test system

Ideally, the amount of the standard added should be recovered at the end of the measurement if the method is accurate.

Pre-analytical activities include: ›collection, labeling, storage, processing, and transportation of specimen.

when 1 control observation exceeds mean +/- 2sd

Red Top/ Tiger Top SST/Gold SST are used for chemistry testing and contain:

is a reference point to determine whether a disease is present or absent, or if a patient is at risk for future disease

žControl ranges for _______ controls must be calculated

Gold standard methods have been established and reproduced across different measurement systems and laboratories.

žUsed to compare the standard deviations of two samples. Can be used to compare test results within the same lab.

Balancing the centrifuge isn't important at all.

______—is the amount of error that can be tolerated without invalidating the medical usefulness of the analytical result

 is the average of a set of numbers

Light gray tops are used for glucose testing and this additive helps preserve glucose for up to 5 days:

Interference studies typically use _____ as an interference

The likelihood of a positive test result in patients with disease; it measures how well the test detects the disease. 

Which color tube isn't a common tube for blood chemistry testing?

QC material is a solution or chemical substance of known concentration that mimics a patient’s specimen. 

reject when 1 control observation exceeds mean +/-  3sd

This rule identifies random error only and can be applied to one control level on consecutive days

is the ability to detect small concentrations of the measured analyte

—_______ is the sum of random and systematic error

›is a process that includes a set of activities that aids in improving the reliability of the laboratory as a whole.