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Breath Test

After a DUI arrest, you will be transported to a police station. After an arrest in Des Moines, Iowa, you will be taken to the Des Moines metro police station. The officer will then ask you to submit to a breath test in the DataMaster testing room.

The Iowa Commissioner of Public Safety has approved the use of either the DataMaster cdm or DataMaster DMT to test a subject’s breath for the presence of alcohol. These are the evidentiary instruments approved for breath testing in the State of Iowa.

The State of Iowa uses more than 170 data masters. Each DataMaster is assigned a different serial number. Many counties in Iowa with a small population have only one DataMaster instrument which is usually located at the  Sheriff’s Office or Jail. Larger police departments in Iowa may have several DataMasters assigned to their agencies.

Attorneys for OWI Breath Tests in Des Moines, IA

If you were arrested for drunk driving and submit to a breath test on the breathalyzer used in Iowa called the Datamaster, then contact an experienced criminal defense attorney who fights these types of cases.

Just because you blew over the legal limit of 0.08 goes not mean that you will be convicted of OWI. Iowa law provides many ways to challenge the accuracy and reliability of breath tests. If the inspectors did not substantially comply with the administrative rules governing the certification and maintenance of the breathalyzer instruments, then your attorney can move to suppress the breath test results so they are not admitted at trial.

Call us today to discuss your OWI breath test result. Call (515) 279-9700 today.

Search Breath Alcohol Testing Data

The Iowa Division of Criminal Investigation Criminalistics Laboratory has created a new searchable system for Breath Alcohol Testing data. The new system makes making some data from the breath alcohol test readily available to the public. Through the website you can find:

  • certification reports and maintenance records on The DataMaster DMT evidential breath instrument;
  • subject breath alcohol test data;
  • officer training records regarding areas specifically regarding training in the field of alcohol testing and collection;
  • instrument certification records; and
  • county statistics.

Iowa’s Breath Alcohol Testing section manages services related to evidential breath test instruments. Criminalists in Iowa’s Breath Alcohol Testing section within the laboratory maintain and certify the evidential breath testing instruments used in the State of Iowa. The Iowa Administrative Code requires that the instruments are certified once a year. To certify the instruments the inspectors run various tests on the units including:

  • accuracy and precision checks;
  • diagnostic checks;
  • radio interference; and
  • volatile compound interference testing.

The testing procedures also use a simulated breath test similar to the one encountered in an OWI testing situation. The laboratory trains law enforcement personnel to operate the instrument. The training is concentrated on how to administer a breath test on a subject. The training does not necessarily cover all of the scientific concepts behind how it works.

What is the DataMaster DMT?

The DataMaster DMT is a scientific instrument designed to analyze a sample of a person‟s breath and determine the Breath Alcohol Concentration (BrAC) in that sample. The DataMaster analyzes the breath sample using infrared absorption spectrometry. The DataMaster analyzes the breath sample using infrared absorption spectrometry.

The checks that the DataMaster performs of itself, the surroundings, and the breath sample are done to ensure that the testing is performed under the most favorable conditions possible.

DataMaster DMT features

  • Heated breath hose – if the breath hose temperature is not within pre-set temperature range the test will not be allowed to proceed.
  • RFI antenna – the antenna is external and part of the breath hose.
  • Three (3) IR filters – the DataMaster DMT has multiple filters to ensure that only ethyl alcohol is being analyzed.
  • Slope Detector – helps with detecting a negative-going alcohol concentration and with assuring that a deep lung sample was provided by the subject.
  • Memory – the DMT can store tests on an SD card for up to one year.
  • Checklist – the DataMaster DMT automatically fills out an operational checklist based on the results of a test.
  • External calibration check – The DMT uses an ethanol dry gas tank to check the calibration with every “RUN” test.
    • The tested value of the external standard has to be within 0.004 or 5%, whichever is greater, of the expected value in order for the test to continue.
    • If the tested value is outside that range, the DMT will indicate a “Standard out of Range” status message.
  • Internal Calibration check – The DMT also performs an internal calibration check with every test.
    • The internal standard value must be within +/- 4% of the value found on the certification report in order for the test to proceed.
    • If this value is outside that range, the test will abort and a status message of “Internal Standard Error” will appear.
  • Diagnostic test – The DMT performs a diagnostic check with every test. If the diagnostic tests fails, the test will abort and the printout will indicate what part of the diagnostic test was outside the parameters set by the manufacturer.
  • Pop-up boxes – The DataMaster DMT has several “pop-up” boxes advising the operator how to proceed. Some of these messages include:
    • instructing the subject how to provide a breath;
    • replacing the mouthpiece, and
    • collecting an alternate sample when a completed test is not obtained.

How Does the DataMaster Work?

The breath test operator can use the main screen to perform the following tasks.


  • Pressing this on the screen initiates the testing procedure (or re-starts it as the case may be).
  • You can also press the “F1” key on the keyboard or use the “Subject Test” in the start menu.
  • This should be used in cases that an evidential breath test is required.

“Non- Memory Test”

  • This testing procedure can be used for the following:
    • Public Intox. cases;
    • work release;
    • verification of a subject’s breath alcohol level is below a facility-set limit for release; or
    • routine practice.
    • An operator does not need to be certified on the DataMaster DMT in order to use the “Non-Memory Test” procedure.


  • Pressing this on the screen provides the operator with an additional copy of the last test performed.

“Reprint test in memory”

  • Pressing this on the screen allows the operator to retrieve a previous test that has been stored in the memory of the DataMaster.
  • Tests will remain in the DMT‟s memory for a period of approximately one (1) year.
  • If the test is no longer in the DMT‟s memory, it may have been uploaded to the DCI server. Please contact the DCI Crime Lab for assistance with retrieving a specific test.

“Dry Gas Tank Change”

  • After a new tank has been installed, the operator can use this tab to input the new tank information by providing the proper password.


  • The DataMaster DMT has three levels of password protection.
  • The general-use password for most applications is _________.
  • The “Change Dry Gas Tank” password (given to those responsible for changing out the tank)
  • DCI Lab personnel use the third password to perform their technical tasks.
  • The “COPY” key is not password protected.
  • If the operator is in a restricted area or enters an incorrect password, the DataMaster will prompt the operator that they do not have a high enough security level.
  • Press “OK‟ to exit.

“Reprinting tests in memory”

  • The DataMaster DMT allows operators to retrieve previous subject tests.
  • Press “Reprint test in memory” on the main screen. – Double-click “Breath Records”.
  • Double-click the date of the test to be retrieved.
  • Double-click the time of the test.
  • Press “Print” on the screen.
  • If you need additional copies, continue to press “Print”.
  • Note – If your test is no longer in the memory, it may have been uploaded to the DCI server and you will have to contact a member of the Breath Alcohol Section of the DCI Crime Lab to obtain a copy.

Non-completed tests

Visual Results

  • The DCI does not recommend the use of “visual” DataMaster test results as evidence. Safeguards are built into the software to prevent the operator from obtaining the alcohol results on any test other than a completed test.
  • If a test is obtained that does not result in a completed test, it is recommended that the operator re-run the test or collect an alternative sample from the suspect.

Non-completed tests

  • A non-completed test is considered to be any test that results in a status message, Incomplete, or Refusal.
  • On tests that do not end in a completed test, the alcohol and breath pattern will appear on the printout. However, there will be no scale associated with the alcohol pattern on the graph section of the printout that could be used to interpret the subject‟s alcohol level. In addition, the alcohol concentration will not appear in the results section of the printout.

Running an Evidential Breath Test

To run an evidential breath test on the DataMaster, the breath test operator will do the following:

  • Press “RUN‟ on the screen or initiate the test through TraCS.
  • If running the DataMaster without the TraCS interface, the DataMaster will ask you to input the following questions:



SEX (M/F):


(first, middle initial, last) (month/day/year)


(letters, numbers, or both)

(two-letter designation only)

(ex. – S.O., P.D., ISP District) (first, middle initial, last)

(letters, numbers, or both)

(enter time-based on 24 hr. clock)

  • Please enter all the information known at the time of the test. If the subject information is not known, the test will be allowed to proceed leaving the fields blank.
  • The “Instrument Location‟ will automatically default to a specific location but
  • “DEPRIVATION TIME‟ will be the time when the operator began the required minimum 15-minute deprivation period. The data entered is to be in the form of a 24-hour clock (ex. – 1 a.m. = 0100, 4 p.m. = 1600). Do not enter the time displayed on the DataMaster.
  • The subject may not eat, drink, smoke, or place foreign objects into the mouth during the minimum 15-minute deprivation period.
  • If the operator were to observe that the subject has tobacco, chewing gum, or any other foreign matter that can be easily removed, the operator must have the subject remove the item.
  • Re-start the minimum 15-minute deprivation period once the item is removed.
  • Dentures – It is not required that the subject to remove dentures prior to submitting a breath sample. However, if the subject wishes to remove dentures, please start the 15-minute deprivation period from the time the dentures are removed.
  • Tongue rings – It is not necessary to remove tongue rings or any other dental or facial jewelry prior to submitting a test on the DataMaster. If removed, please begin the deprivation period from the time they are removed.
  • Belching – belching or burping does not require a re-start of the deprivation period.
  • Vomiting/regurgitating – If the subject should vomit/regurgitate during the deprivation time the operator may allow the subject to rinse his/her mouth with water and must restart the 15-minute deprivation period from that point.
  • Inhalers – The use of an inhaler prior to a breath test is allowed. Re-start the 15 minute deprivation period from the completion of the use of the inhaler then test the subject on the DataMaster after the deprivation period has elapsed.


To run the breath test, the operator will do the following:

    • Enter the information –Blank Test
    • Diagnostic Check
    • Internal Standard
    • External Standard – Blank Test
    • Subject Sample
    • Subject Sample
    • Blank Test
  • The DCI recommends that the officer instruct the subject to “provide a long and steady breath through the mouthpiece”. However, other instructions given to the individual on how to provide a breath will not bias a test against the subject.
  • Note – the mouthpiece can be placed onto the breath hose at any time before the subject providing a breath into the instrument. Avoid putting the mouthpiece on while the DMT is in a “TIMED PURGE” mode.
  • After you press “OK” – the DataMaster will proceed to run the initial quality assurance tests. This includes:
    • Blank test
    • Diagnostic test
    • Internal Standard Check
    • External Standard Check
    • Blank test before the subject providing a breath sample.
  • This takes approximately 2 minutes to perform.
  • The “Instruct the subject to blow long and steady…” box will remain on the screen for two minutes or until the officer presses “OK‟.
  • Press the “OK‟ on the screen prior to the subject beginning their breath.
  • After two minutes without a response from the operator to the prompt noted above, the DataMaster will automatically go to the next step and will begin the two-minute breath phase.
  • When it is ready, the DataMaster will prompt the subject with a single beep and a flashing “PLEASE BLOW‟ on the bottom left of the display.
  • When the subject is blowing at or above the minimum flow rate, the DMT will have a solid, audible tone.
  • If this is not occurring, it is permissible to instruct the subject to “blow harder‟ to inform the subject that his/her breath sample flow must be at a flow rate considered acceptable by the DataMaster.
  • A solid “PLEASE BLOW’ and continuous tone must be maintained throughout the delivery of the breath sample to satisfy one of the sample requirements.
  • A “break‟ in the continuous flow of a breath sample will result in the return of the flashing “PLEASE BLOW’ and the DMT becoming silent and restarts the minimum volume and time requirements. (Unless the sample is accepted by the DMT).
  • The subject has two minutes from the beginning of the breath phase to provide an adequate breath sample.

Breath Profile Screen

The breath test operator will use the profile screen to do the following:

  • The DataMaster DMT allows the operator to view the breathing pattern of the subject’s breath delivered into the instrument as the person is providing a breath (or not providing a breath).
  • The breath pattern will be blue in color on the screen.
  • Note – the alcohol graph will not be displayed while the subject is providing a breath but will be part of the final printout.
  • The subject has reached the necessary volume requirement when the green bar graph has passed the designated line.
  • However, the goal is still to have the subject provide a steady breath for as long as they can.
  • The subject does not need to blow for the entire two minutes; only long enough to satisfy the DataMaster’s requirements as to an acceptable sample. This may take several seconds though the time will vary from subject to subject.
  • The DataMaster has four requirements for the acceptance of a breath sample:
    • a continuously delivered breath for a minimum time of 4 seconds
    • a minimum breath volume of 1.3 Liters
    • a minimum breath flow rate of 3 L/min satisfaction of the slope detector requirements
  • Once all four requirements are met, the DataMaster will accept the breath once the subject has stopped blowing into the instrument (see note below).
  • Note – the DataMaster DMT will automatically accept the breath sample when the subject delivers a continuous breath of approximately 3.0 Liters.
  • When the DataMaster has accepted a sample, the display will read: ANALYZING
  • The DataMaster will prompt the officer to remove the mouthpiece – press “OK” when complete. (Note – the mouthpiece may have already been removed prior to the prompt by the DataMaster)
  • The DataMaster will analyze the sample twice and then perform its final checks. After the completion of its final checks, the DataMaster will prompt the operator to sign the screen and will then print out the results.
  • If there is a difference between the test results then the lower of the two test results is to be used.
  • Three (3) copies of the results should print; one for the county attorney, one for the operator performing the test, and one for the subject. (The number of copies may vary depending on departmental request)
  • Two (2) copies of the checklist should print. If additional copies of the checklist are needed, please make a photocopy of the original or press the “COPY” key.
  • For those utilizing the TraCS system, only one copy will be printed by the DataMaster. Press the “COPY” key on the DataMaster if additional copies are needed.
  • The DataMaster DMT has an operational checklist that is filled out by the DataMaster every time a “RUN” test is performed.
  • Please ensure that the checklist is filled out properly based on the test sequence that was performed.

Incomplete or Refusal

If the breath test shows an incomplete reading or a refusal, then the breath test operator is trained to do the following:

  • “Did the subject refuse? (YES/NO)” will be asked if the DataMaster has been allowed to go through the 2-minute breath-sampling period without an adequate sample having been provided.
  • If this question is answered with a “YES” the printout will indicate “SUBJECT SAMPLE REFUSED”.
  • If this question is answered with a “NO” the printout will indicate “SUBJECT SAMPLE INCOMPLETE”.
  • If the subject has met the time, volume and flow rate requirements at any point during the breath phase, but does not meet the slope detector requirements – the operator will not be able to call the test a REFUSAL. The DMT will automatically call the test an INCOMPLETE test.