Blood Stability Score (BSS)

Scope: This Q&A is based on the introduction of the Blood Stability Score (BSS) for Athlete Biological Passport (ABP) blood samples, which goes into effect early 2017. The specific steps for the implementation of the BSS are detailed in Annex K of the International Standard for Testing and Investigations (ISTI), and the Technical Document for Blood Analytical Requirements for the Athlete Biological Passport (TD2017BAR), both of which can be found as appendices in the ABP Guidelines.

Explanation of Abbreviations:

ABP: Athlete Biological Passport
ADO: Anti-Doping Organization
APMU: Athlete Passport Management Unit
BCO: Blood Collection Officers
BSS: Blood Stability Score
CAT: Collection to Analysis Time (the total time between collection of the sample and the analysis of the sample at the laboratory)
CRT: Collection to Reception Time, (the time between collection of the ABP blood sample from the athlete by the DCO/BCO and the reception of the sample by the laboratory)
DCO: Doping Control Officer
RAT: Reception to Analysis Time (the time between reception of the sample by the laboratory and the analysis of the sample)
SCA: Sample Collection Authority
TA: Testing Authority

Note that CAT = CRT + RAT

  1. What is the Blood Stability Score (BSS)?
  2. What are the benefits of implementing the BSS?
  3. How is the BSS calculated?
  4. What is the maximum permitted transport time using the BSS?
  5. How was the maximum permitted BSS established?
  6. How does the BSS change the way an Anti-Doping Organization (ADO) plans an ABP blood sample collection mission?
  7. Can you provide an example of how to use the BSS to plan a mission with extended transport time?
  8. What do the Sample Collection Authorities (SCA) and their Doping Control Officers (DCOs)/Blood Control Officers (BCOs) need to do differently following the implementation of the BSS?
  9. How is the temperature data logger ID and time zone information entered into ADAMS?
  10. Why is it important to use the GMT (Greenwich Mean Time) time standard?
  11. What will the labs need to do differently following the implementation of the BSS?
  12. Can the laboratory assess the remaining time for analysis for a given sample?
  13. What happens to the sample when the BSS cannot be calculated?
  14. Will the temperature data and the resulting BSS calculated for the sample be available in ADAMS?
  15. What types of temperature loggers (aka data loggers) are compatible with the BSS?
  16. How was the BSS validated?
  17. With this new system, can we now re-validate older samples collected prior to the BSS?
  18. What happens if the DCO/BCO forgets to start the data logger before the sample collection?
  19. Can one data logger be used for multiple samples?
  20. Can data loggers be reused with the same ID?
  21. What previously published studies supported the extension of the blood transport time?

1. What is the Blood Stability Score (BSS)? Up

The BSS is a quality index for ABP blood samples that takes into account the relationship between the temperature of the sample during transport and the duration of time between sample collection and analysis. The BSS will be calculated in ADAMS for all ABP blood samples. A lower BSS reflects shorter transport times at cooler temperatures. Conversely, a sample transported for longer times and/or at higher temperatures will have a higher BSS which implies that there is a higher risk that the sample presents some signs of deterioration. A conservative threshold has been set at 85, below which the sample will be considered as valid in ADAMS.

2. What are the benefits of implementing the BSS? Up

The benefits are twofold:

  1. An extension of transport time of ABP blood samples, with an enhanced possibility to collect samples in remote areas and during week-ends;
  2. Standardization of the storage and analysis of temperature data with a reduced workload for all parties.

3. How is the BSS calculated? Up

The BSS will be calculated in ADAMS using the data from the temperature logger that accompanied the blood sample according to the following formula:   

BSS = 3*T  + CAT

Where CAT is the Collection to Analysis Time, and T is the average temperature of the sample during that period. In order to insure the stability of the markers used in the haematological module of the ABP, the BSS should not exceed 85. All samples with a BSS greater than 85 will be made invalid in ADAMS.

As an example, a sample that was transported to the lab in 33 hours and was analyzed by the lab in 2 hours (CAT of 35 hours) and was kept at an average temperature of 6°C, the BSS could be calculated as follows:

BBS = 3*6 + 35 = 53

Here the calculated BSS is less than 85 so the sample would be valid in ADAMS.

4. What is the maximum permitted transport time using the BSS? Up

This depends on the average temperature of the sample during transport, keeping in mind that the sample must never freeze (frozen samples will be invalidated in ADAMS). For an extended transport time of several days, an average temperature of 4°C should be the lowest reasonable target temperature that would minimize the risk of the sample freezing. At 4°C, using the formula above and the maximum BSS of 85, the maximum permitted CAT would be 73 hours.

The following table describes the maximum collection-to-reception times (CRT) for samples transported at a given average temperature, while still allotting 12 hours for the analysis at the laboratories:

When properly coordinated with the laboratory, the CRT could be extended even further by reducing the time to analysis to less than 12h.

5. How was the maximum permitted BSS established? Up

The maximum BSS of 85 is a conservative limit based on the findings of previously published studies (listed below), and then validated using real anti-doping samples (Robinson N, 2016).

6. How does the BSS change the way an Anti-Doping Organization (ADO) plans an ABP blood sample collection mission? Up

The scheduling of blood collection missions remains for the most part unchanged and samples should still be sent to the laboratory as soon as possible within established criteria. In particular, routine missions where the sample is adequately cooled and arrive at the lab within 36h will remain valid.

However, the BSS will allow the extension of the Collection-to-Analysis Time (CAT) from the present 48 hours up to 72 hours which will improve the ability to test in remote areas, as well as on weekends when laboratories have restricted operating hours. The Anti-Doping Organization /Sample Collection Authority (SCA) will need to ensure proper communication with the laboratory in order to ensure the reception-to analysis time (RAT) is in line with the overall CAT of the planned mission.

7. Can you provide an example of how to use the BSS to plan a mission with extended transport time? Up

The previously mentioned table (T and CRT) provides guidance on the maximal allowed transportation time when the specifications of the cooling box are known. The mission should be planned using a conservative approach in case there are any delays in transportation and/or any increase in temperature.

As an example, suppose an ADO wishes to test an athlete in a remote area where the estimated transport time to arrive at the nearest laboratory is 50 hours. They typically use a cooling box that can maintain an average temperature of 5°C. Based on the table above, the time between the collection and the reception (CRT) for a sample maintained at an average temperature of 5°C should not exceed 58 hours. Thus, the planned duration of the mission is 8 hours less that the maximum permitted CRT. This will provide some degree of flexibility should there be some small deviations in the average temperature and possibly up to an 8 hour buffer in case there are any delays in transportation.

8. What do the Sample Collection Authorities (SCA) and their Doping Control Officers (DCOs)/Blood Control Officers (BCOs) need to do differently following the implementation of the BSS? Up

1. The DCO/BCO must use a transport device and cooling system in line with the projected duration of the mission, ensuring that the sample never freezes.
2. The DCO/BCO shall set up the temperature data logger to measure the time in Greenwich Mean Time (GMT) and record the temperature once per minute.
3. The DCO/BCO shall start the temperature data logger and place it in the storage device. Whereas prior to the BSS, the standard practice was to start recording the temperature after the sample is placed in the storage device,  upon launching of the BSS it is important to start recording the temperature before sample collection.
4. Indicate the temperature data logger ID (as written on the logger) and the time zone of the testing location in GMT. This information can be written on the chain of custody documentation or directly into ADAMS if the DCO/BCO has access to ADAMS.
 

9. How is the temperature data logger ID and time zone information entered into ADAMS? Up

To allow greater flexibility for users, these two fields will be available in the Doping Control Form (DCF), Quick DCF, and Chain of Custody forms. In the situation where many samples are shipped together with the same data logger, a function will be available in the Quick DCF table to apply the same data logger ID and time zone information to multiple samples. Alternatively, the Chain of Custody form can also be used to associate a single data logger ID and time zone to multiple samples.

10. Why is it important to use the GMT (Greenwich Mean Time) time standard? Up

For samples analyzed in a time zone different than the collection site, the CAT can only be properly calculated using a time standard. To achieve this, 1) the data logger must record time in GMT, 2) the DCO/BCO (alternatively the SCA or TA) should report the time zone of the collection site in GMT in ADAMS, and 3) the laboratory should indicate the local time relative to GMT in ADAMS. With these three pieces of information, ADAMS can calculate the CAT regardless of any time differences between the location of sample collection and the laboratory.

11. What will the labs need to do differently following the implementation of the BSS? Up

1. In cases where the laboratory is unable to analyze the sample immediately after reception, the laboratory shall be responsible for maintaining the sample at a cool temperature (approximately 4°C) from the time of reception to the start of the analytical procedure.
2. The temperature data logger must accompany the sample until sample homogenization.
3. The temperature data logger must be stopped before sample homogenization.
4. The laboratory must upload into ADAMS the raw temperature profile recorded by the temperature data logger by plugging the device into a computer USB port and renaming the file (as indicated in the TD2017BAR) and include the data logger ID and date of reception. A dedicated import function is made available for that purpose from the user’s ADAMS main page.
5. The laboratory must report the temperature profile before the test results of the sample.
6. The laboratory will be responsible for updating their local time relative to GMT twice a year in ADAMS, where applicable, for daylight savings time.
 

12. Can the laboratory assess the remaining time for analysis for a given sample? Up

No, the laboratory would only be aware of the approximate remaining time for analysis if such information is communicated by the DCO/BCO. Otherwise, the laboratory should analyze the sample as soon as possible, and with a delay of up to 12h if necessary.  For example, a sample with a CRT of 30 hours that has been transported in ideal conditions could still be analyzed up to 40 hours later. However since the laboratory is usually not aware of the transport time and conditions they should always analyze the sample as soon as possible. In any case, analysis and evaluation of samples is recommended for a number of reasons.

13. What happens to the sample when the BSS cannot be calculated? Up

In cases when the BSS cannot be calculated, the blood sample will remain valid. The validity of these samples will need to be monitored by the Athlete Passport Management Unit (APMU), in conjunction with the panel of Experts as required.

14. Will the temperature data and the resulting BSS calculated for the sample be available in ADAMS? Up

Yes. The BSS will be available as an optional column in the results table of the athlete’s passport page. The BSS will be displayed as “N/A” in cases where it cannot be calculated. The temperature profile will be available in graphical form together with the time of collection, time of reception and time of analysis. This will insure that the temperature data is readily available to experts and in an ABP Documentation Package as required.

15. What types of temperature loggers (aka data loggers) are compatible with the BSS? Up

The temperature data logger used will need to fit the following criteria:

  • record the temperature in degrees Celsius at least once per minute;
  • record time in GMT;
  • report the temperature profile over time in text format with one line per measurement following the format “YYYY-MM-DD HH:MM T”;
  • have a unique ID of at least six characters;
  • have a USB interface.

Both one-time use and re-usable data loggers can be utilized as soon as they fit the above criteria. In case of the purchase of new data loggers, it is recommended to verify with the seller that the type of data logger fulfil all the above criteria and more particularly the capability to report the data in text format.

16. How was the BSS validated? Up

The BSS was first created based on the findings from previously published studies examining blood sample stability (see list below). The BSS was then validated in a study using real anti-doping samples that were analyzed according to the current criteria (CRT < 36h, CAT <48h), and then stored and analyzed again at a later time. This study demonstrated that when samples are maintained at a suitably cool temperature, the CAT can be extended without compromising the integrity of the markers used in the haematological module of the ABP.

17. With this new system, can we now re-validate older samples collected prior to the BSS? Up

No. The BSS will only apply to samples from the date of implementation forward. (In rare cases, an older invalidated sample could be revalidated by a recommendation from a combination of laboratory and haematological experts based on detailed analysis of sample indices and other information).

18. What happens if the DCO/BCO forgets to start the data logger before the sample collection? Up

If the time the data logger is started is after the sample collection time reported by the DCO/BCO, then the BSS cannot be calculated for this sample. The sample will remain valid and will then need to be assessed by the APMU.

19. Can one data logger be used for multiple samples? Up

Yes. A single data logger placed in a cooling box that contains multiple samples is good practice as long as the data logger starts recording the temperature before the collection of the first sample. The laboratory will have to upload the raw temperature profile only once independently of the number of samples present in the cooling box. ADAMS will take care of matching the data logger with the samples in order to compute the BSS.

20. Can data loggers be reused with the same ID? Up

Yes. This is made possible by the manner in which the labs enter the data logger ID, which is a concatenation of the data logger ID and the date of reception of the sample (see section 6 of TD2017BAR).

21. What previously published studies supported the extension of the blood transport time? Up

The following published scientific articles provided the basis for the development for of the BSS (in chronological order):

  1. Brittin GM, Brecher G, Johnson CA, Elashoff RM. Stability of blood in commonly used anticoagulants. Use of refrigerated blood for quality control of the Coulter Counter Model S. Am J Clin Pathol. 1969;52(6):690-4.
  2. Wood BL, Andrews J, Miller S, Sabath DE. Refrigerated storage improves the stability of the complete blood cell count and automated differential. Am J Clin Pathol. 1999;112(5):687-95.
  3. Bourner G, Dhaliwal J, Sumner J. Performance evaluation of the latest fully automated hematology analyzers in a large, commercial laboratory setting: a 4-way, side-by-side study. Lab Hematol. 2005;11(4):285-97.
  4. Lippi G, Salvagno GL, Solero GP, Franchini M, Guidi GC. Stability of blood cell counts, hematologic parameters and reticulocytes indexes on the Advia A120 hematologic analyzer. J Lab Clin Med. 2005;146(6):333-40.
  5. Voss SC, Flenker U, Majer B, Schänzer W Stability tests for hematological parameters in antidoping analyses. Lab Hematol. 2008;14(3):24-9.
  6. Hill VL, Simpson VZ, Higgins JM, Hu Z, Stevens RA, Metcalf JA, Baseler M. Evaluation of the Performance of the Sysmex XT-2000i Hematology Analyzer With Whole Bloods Stored at Room Temperature. Lab Med. 2009;40(12):709-718.
  7. Robinson N, Sottas PE, Pottgiesser T, Schumacher YO, Saugy M. Stability and robustness of blood variables in an antidoping context. Int J Lab Hematol. 2011;33(2):146-53.
  8. Oddoze C, Lombard E, Portugal H. Stability study of 81 analytes in human whole blood, in serum and in plasma. Clin Biochem. 2012;45(6):464-9.
  9. Briggs C, Longair I, Kumar P, Singh D, Machin SJ. Performance evaluation of the Sysmex haematology XN modular system. J Clin Pathol. 2012;65(11):1024-30.
  10. Ashenden M, Clarke A, Sharpe K, d'Onofrio G, Plowman J, Gore CJ. Stability of athlete passport parameters during extended storage. Int J Lab Hematol. 2013;35(2):183-92.
  11. Zini G, International Council for Standardization in Haematology (ICSH). Stability of complete blood count parameters with storage: toward defined specifications for different diagnostic applications. Int J Lab Hematol. 2014 Apr;36(2):111-3.
  12. Ashenden M, Sharpe K, Plowman J, Allbon G, Lobigs L, Baron A, Gore CJ. Stability of athlete blood passport parameters during air freight. Int J Lab Hematol. 2014;36(5):505-13.
  13. D'Alessandro A, Kriebardis AG, Rinalducci S, Antonelou MH, Hansen KC, Papassideri IS, Zolla L. An update on red blood cell storage lesions, as gleaned through biochemistry and omics technologies. Transfusion. 2015 Jan;55(1):205-19.
  14. Joshi A, McVicker W, Segalla R, Favaloro E, Luu V, Vanniasinkam T. Determining the stability of complete blood count parameters in stored blood samples using the SYSMEX XE-5000 automated haematology analyser. Int J Lab Hematol. 2015;37(5):705-14.
  15. Sudmann-Day ÅA, Piehler A, Klingenberg O, Urdal P. Six-day stability of erythrocyte and reticulocyte parameters in-vitro: a comparison of blood samples from healthy, iron-deficient, and thalassemic individuals. Scand J Clin Lab Invest. 2015;75(3):247-53.
  16. Robinson N, Giraud S, Schumacher YO, Saugy M. Influence of transport and time on blood variables commonly measured for the athlete biological passport. Drug Test Analysis. 2016;8(2):199-207.