Workflow In The Coagulation Laboratory

by Donna Castellone, MS, MT(ASCP)S • February 07, 2024

The interpretations below are provided by Donna Castellone, MS, MT (ASCP) SH for Aniara Diagnostica.

Everything seems to be unpredictable these days! One thing that is predictable is that laboratories are busier than ever, and staffing is probably at its lowest. The first laboratory I worked in had 25 (yes 25!) techs in hematology. Granted things were more manual, BUT there were technologists who were "checkers" who reviewed questionable cells on slides, we had 10 people doing specialty testing (over the 25 in hematology). It was a 1900 bed hospital. I learned a lot! Now you are lucky if you have one person per bench.

So, how can laboratories survive? Let's look at workflow. What can be done to make testing more efficient while maintaining quality. Does having total laboratory automation help this? Remember that was going to be the answer/solution for laboratories. It was discovered that you still need technologists to troubleshoot and review critical results as well as calling those results to the floors, which is an endless task.

Laboratory performance has improved with the automation of pre-analytical, analytical and post-analytical processes which is utilized in Total Laboratory Automation (TLA). However, this comes with several issues. It requires a lot of space, high short-term costs, possible bottlenecks and still requires manual work requiring sample tracking, retrieval, and manual reloading.1 Modular work cells may work better and be more flexible and require less space.

There are several other solutions that can be implemented that can help laboratories.

Pre-Analytical Solutions:

Specimen quality which includes the use of HIL (hemolysis, icteric, lipemia) can help laboratories. Chemistry laboratories have been using this automated detection for years, coagulation testing has not. Currently this is done manually and can be time consuming and difficult to standardize. Having this automated has pro's and con's. It takes the job off the technologist. and it will standardize the process. However, laboratories need to understand what is the impact on their results based on the level of interference, is it clinically significant? What is the status of the patient or is the hemolysis due to an improper draw. Levels of detection for rejection should be determined by individual laboratories based on their patient population.2

Centrifugation is a crucial step in processing coagulation samples. It is important to work with platelet poor plasma. This is defined as plasma having a platelet count of less than 10,000. Since coagulation reagents are made of phospholipids, platelets are also made of phospholipids and the presence of them in plasma can shorten coagulation results, this is mandated by CAP. This recommended by CLSI guidelines (H21-A5) is this is required for special coagulation testing, however up to 200×109/L can be used for PT and aPTT testing.3 Meeting this lower platelet count means laboratories need to spin samples for a minimum of 15 minutes which can impact turnaround time.

Studies have shown that increasing the centrifugation speed and decreasing the spin time (4000g for 5 minutes versus 2000g for 10 minutes) found no impact on clinical diagnosis or patient management for routine testing. This can greatly improve TAT by revising the plasma preparation protocol.4 This would require a side by side study to prove that this works with your instrument/reagent combination. It also needs to be proven based on your package insert from your manufacturer reagents which has been FDA approved and may suggest a longer centrifugation time.


An individualized approach should be used to determine the most efficient workflow when using POC coagulation testing. The closer to the patient, the quicker the result. POC testing is most accurate in clinics- cost effective and better care quicker, biggest bang for your buck with reimbursement. However, when you start using this for higher volume testing there can be limitations. PT/INR tests are approved for warfarin clinics, using them in the ICU can be challenging. One POC analyzer uses an electrochemical endpoint that is insensitive to fibrinogen resulting in a normal PT regardless of fibrinogen levels.2 The use of POC testing can be very beneficial in the correct situation but must be monitored by the laboratory as this is their responsibility as per regulatory requirements. This can be time consuming and require additional resources.


In order to minimize time spent troubleshooting implementing electronic ordering along with rules can improve the quality of testing. This should mandate the order to include the presence or absence of anticoagulation including warfarin, heparin, and DOACs.

A study looked at 362,692 APTT, PT/INR and fibrinogen. If no anticoagulation was present and the result is abnormal, second line testing such as fibrinogen, thrombin time or even mixing studies would be performed. If a mixing study did not correct, or a fibrinogen was below 100g/dL, or an INR elevated, results were flagged for clinical review. 5 Of these, 14,160 (3.9%) were abnormal with either no reported anticoagulant, or an unknown anticoagulant status. A total of 934 (0.3%) were referred for review. Three (&llt;0.001%) cases received altered medical management.5

In hospital settings, most abnormal coagulation studies are anticipated by the ordering clinician. Unexpected abnormal coagulation results of clinical significance are rare. Automated second line coagulation testing and medical review improves laboratory workflow without compromising patient safety.5

Autoverification rules for routine coagulation tests can greatly reduce the TAT and ensure accuracy when compared to manual verification. A study looked at 22,072 coagulation results. Rules were designed with reference to CLSI Auto 10A guidelines which included a QC check, consistency checks, sample quality check, alarm check, critical value check, delta check, limit range check and logical rules check.6

Auto-verification rules were configured in a middleware (HemoHub) and 14,642 samples results were verified by the auto-verification rules. The overall passing rate was 69.5%. Auto-verification significantly decreased the mean laboratory TAT from 90.8 min to 71.8 min (P = 0.006).6

Use of data management systems can be used in routine coagulation testing to reflex and rerun samples. These systems use algorithms to not only reflex testing but to incorporate and entire workflow either automatically or manually based on individual laboratories need. These can also be developed to assist with special coagulation testing for lupus as well as factor assays. These rules can help to determine how testing should proceed and standardize reports. Rules would be written and developed by the laboratory with assistance from the manufacturer. It is important to understand this will require initial and periodic evaluation from the testing to reporting process.2


The coagulation laboratory does have options and they can definitely help to improve turn around time as well as not compromise quality. Improving workflow is not one size fit all, it needs to be done by a purposeful analysis for individual laboratories based on size, volume of testing and the comfort level of the technologists.


  1. Lee, HT, Lee, SY, Seo, JY, Ahn, JY, Short term experience of a Modular Workcell for Hemostasis Testing Including an Intelligent Data Manager at a Tertiary Care Hospital, Laboratory Medicine, 2023, 495-501.
  2. McGonnagle, B., Salazar, E., Higgins,R., et al. Volume? Space? Automation decisions in coagulation, CAP Today, January 2023
  3. Clinical and Laboratory Standards Institute: Collection, transport, and processing of blood specimens for testing plasma-Based coagulation assays and molecular hemostasis aAssays; approved guideline H21-A5, 5th ed. Wayne, PA: CLSI, 2009: 5-15.
  4. William Quirke, Zubir Koohestani, Revisiting coagulation centrifugation protocol for integration into total laboratory automation workflow Journal of Laboratory and Precision Medicine, (5) April 2020.
  5. Richard Blennerhassett, Emmanuel Favaloro, Leonardo Pasalic, Coagulation studies: achieving the right mix in a large laboratory network, Haematology, (51)7, 718-722, December 2019.
  6. Linzi Miao a, Chuanbao Li b, Juhua Dai c, Run Wang a, Jing Zhang d, Huiming Ye d, Qingkun Fan e, Huixia Lu f, Hai Wang g, Yanli Zhao h, Xiaoxia Li i, Baiqing Wu j, Lijiao Xia k, Chuanjin Zhu l, Yang Shen m, Wei Xu n, Chenxue Qu a, A multicenter study for establishment and evaluation of auto-verification rules for routine coagulation tests. Informatics in Medicine Unlocked, Volume 32, 2022,