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The Role of the Clinical Laboratory – Interview with Dr. Polya Penkova
Interview with Dr. Polya Penkova, Head of the Clinical Laboratory: “We are the department that works behind the scenes, yet one that is essential for a hospital to function.”
06.10.2025 | 09:53
The Clinical Laboratory at Nadezhda Hospital performs a wide range of tests for the prevention, diagnosis, and screening of various diseases, as well as for monitoring patients throughout their treatment and recovery in all hospital departments.
The laboratory’s services are available at both of our locations: Nadezhda Hospital, 3 Blaga Vest Street, and Nadezhda Medical Center, located on the 3rd floor of Paradise Center.
In addition to routine laboratory testing that supports the needs of a multidisciplinary hospital, the laboratory also performs specialized tests related to the diagnosis and treatment of patients in the fields of reproductive medicine, virology, and medical oncology.
Dr. Polya Penkova graduated in Medicine from the Medical University of Sofia in 2003. In 2013, she obtained her specialty qualification in Clinical Laboratory Medicine from the same university. From 2003 to 2004, she worked as a physician in the Clinical Laboratory of St. Vrach and St. Kuzma and Damyan Medical Center in Sofia.
In 2004, she joined the Clinical Laboratory of Queen Joanna University Hospital, where she worked primarily in the field of hematology, with a particular focus on pediatric oncohematology. Since 2014, she has served as Head of the Clinical Laboratory at Nadezhda Hospital.
Dr. Penkova has extensive experience in clinical trials and works in close collaboration with the team of the Medical Oncology Clinic at Nadezhda Hospital.
Her professional interests include hematology, endocrinology, tumor markers, and laboratory testing in prenatal diagnostics.
1. Dr. Penkova, what is the role of the Clinical Laboratory? Is it even possible for a hospital to function without this important department?
We are the department that works behind the scenes, yet one that is essential for a hospital to function. It is much like in the movies: we are neither the director nor the cinematographer, and certainly not the lead actors. And yet, without the people behind the camera, there would be no movie at all. So the answer is no – a hospital could not exist or function effectively without a clinical laboratory.
Here at Nadezhda Hospital’s Clinical Laboratory, nearly 400 patients pass through our doors every day. We perform a broad spectrum of tests used for prevention, diagnosis, and screening of various diseases, as well as investigations related to the treatment and monitoring of patients across all hospital departments.
These include hematology and biochemistry tests, hormone and tumor marker analyses, inflammatory and sepsis markers, coagulation studies, vitamin testing, urinalysis, and many other laboratory investigations.
2. Which hospital departments do you collaborate with most frequently?
Collaboration and teamwork are fundamental values at Nadezhda Hospital. Colleagues from all departments rely on us for information related to laboratory testing in their clinical cases. We discuss when and how specific tests should be performed and review the results together. Whenever we receive a critical laboratory result, regardless of the department or specialty involved, we immediately alert the treating clinicians so that timely action can be taken.
It is precisely through this close collaboration that we are able to introduce new laboratory tests tailored to the needs of the hospital’s medical practice.
We work closely with the hospital’s other nine laboratories, all clinical departments, and the individual physicians and consultants at Nadezhda. This collaboration clearly demonstrates the importance of the Clinical Laboratory. Let me give you a few examples.
Our laboratory is responsible for collecting blood samples for testing in the Virology, Genetics, Immunology, Research, and Chemistry Laboratories. We also work closely with the Microbiology Laboratory, particularly in relation to urine testing. We compare their findings with our own results and evaluate the correlation between them. This approach enables much more precise diagnostics and, consequently, the selection of the most appropriate treatment strategy.
We are an integral part of the processes related to the treatment of infertility at Nadezhda and work in close collaboration with the specialists in the Assisted Reproduction Unit. This cooperation goes far beyond hormone monitoring during IVF procedures. It plays a role in the overall treatment strategy and in tailoring care to the individual needs of each patient.
We maintain ongoing communication with all other hospital departments, including Obstetrics and Gynecology, the Intensive Care Unit, the Medical Oncology Clinic, and Neonatology.
Our colleagues in Prenatal Medicine present us with particularly fascinating challenges, such as laboratory investigations associated with intrauterine blood transfusions. We are responsible for measuring the baby’s hemoglobin levels before and after the transfusion is performed in the mother’s womb.
We are also in constant discussion with our Neonatology colleagues about how we can further improve diagnostics for our youngest patients and reduce the need for antibiotic use whenever possible.
We maintain equally close contact with the Medical Oncology Clinic. Together, we have established strict workflows and procedures that ensure not only highly accurate but also exceptionally rapid laboratory results for oncology patients.
Whenever there are emergency patients in the Intensive Care Unit or operating theatres, laboratory tests are prioritized and processed within extremely short timeframes. In some cases, a complete panel of results is available within no more than 15–17 minutes of the sample arriving in the laboratory.
The fact that this communication exists between us ultimately benefits the patient. It enables rapid response to critical laboratory findings, supports accurate diagnosis, and ensures timely treatment.
3. How important is the equipment in a clinical laboratory?
Of course, technology is extremely important for the quality of our work. In this regard, we continuously invest in new and modern equipment and work with state-of-the-art analyzers. I would like to emphasize that, as laboratory specialists, we have been given the opportunity to select these instruments ourselves. We have hematology, biochemistry, and immunology analyzers, as well as systems for urinalysis, coagulation testing, blood gas analysis, vitamin testing, and more.
However, equipment alone is not enough. If you drive a Formula 1 car, does that automatically make you a Formula 1 driver? Of course not. An analyzer is a machine. Choosing the right analyzer is important, and we have selected the very best. Equally important, however, is who operates the instrument, how it is maintained, and who evaluates, interprets, and validates the results.
4. Naturally, this leads to the question: what is the team you work with like?
Our team consists of 16 exceptionally well-trained professionals. Most of us work at the hospital due to the workload and the 24-hour nature of our operations, while the rest are based at our Clinical Laboratory in Nadezhda Medical Center at Paradise Center. I am extremely proud of every member of the Clinical Laboratory team.
It is easy to bring people together to work side by side, but it is much more difficult to build a true team. Here, everyone has their place in this complex yet well-coordinated machine called the Clinical Laboratory. These are experienced professionals who work with dedication and genuinely love what they do. The success of our laboratory is owed entirely to them.
5. What are the laboratory’s working hours, and where can patients find you?
We operate two laboratories. One is located at Nadezhda Medical Center in Paradise Center and is open seven days a week. The second is located at Nadezhda Hospital and operates 24 hours a day, seven days a week.
During the night, our services are available to hospital departments, admitted patients, and patients attending the Emergency Outpatient Office at Nadezhda Hospital.
Both laboratories have the equipment and capacity to perform the full range of laboratory tests offered by Nadezhda. They operate within the same information system, shared by both the hospital and the medical center. As a result, all information is stored in a single patient record and is accessible to all Nadezhda physicians.
If laboratory tests are ordered at the hospital, patients may choose to have them performed at the Medical Center in Paradise Center, and vice versa. We function as one integrated system. The important thing is which location is most convenient for the patient.
6. Which laboratory tests are most commonly requested by your patients?
Given the hospital’s areas of expertise, a large proportion of the tests we perform are related to assisted reproduction, obstetrics and gynecology, pregnancy monitoring, neonatology, medical oncology, and pediatric healthcare.
The most frequently requested tests include hormone assays, vitamin testing, complete blood counts (CBC), inflammatory markers such as C-reactive protein (CRP)—particularly at Nadezhda Medical Center due to the presence of pediatric specialists—tumor markers, oral glucose tolerance tests, preeclampsia screening, biochemical screening during pregnancy, and many others.
7. How do you ensure the accuracy of laboratory results?
We ensure accuracy through daily quality control procedures using certified control materials, regardless of whether it is a regular working day, a weekend, or a public holiday.
We maintain a backup instrument for every analyzer. If we obtain a result that is, for example, outside the expected reference range, we repeat the test on the second analyzer. If necessary, we recalibrate the instrument and repeat the quality control process. We also discuss the findings with the treating physician and correlate the laboratory result with the patient’s clinical condition. Every result is carefully reviewed and considered before it is validated and released.
8. Are there any less common laboratory tests that patients can have performed at Nadezhda?
Yes. One example is the Anti-Xa activity test, which is used to monitor therapy with low-molecular-weight heparins such as Fraxiparine. Based on the results of this test, the dosage of these anticoagulant medications can be adjusted accordingly.
We have also recently introduced testing for essential and toxic elements, including zinc, selenium, mercury, lead, cadmium, and others.
9. How long does it take for Clinical Laboratory results to be ready?
In general, a complete blood count (CBC) is available within a maximum of 20 minutes, while biochemical tests are ready within approximately 1.5 hours. Blood pregnancy tests, hormone assays, and tumor marker analyses are typically available within no more than two hours.
10. What are the most common myths you encounter when working with patients?
There are many misconceptions that we come across. One of them is that laboratory results take a long time to be processed. We disprove that assumption every day.
Another common myth is that a clinical laboratory is only responsible for drawing blood. Most people are unaware of how much work takes place behind the scenes before a final result is produced and validated.
There is also a misconception that laboratories only work with outpatient patients during the morning hours. At Nadezhda, we provide services to outpatients from early morning until late evening.
Many people believe that they must avoid drinking water for 10–12 hours before a blood test. In fact, drinking a small amount of water—and only water—is generally allowed and is required for only certain laboratory tests. The exception is when a patient is scheduled to undergo a procedure under anesthesia.
Another myth is the belief that some people simply have “difficult veins.” In reality, there are no difficult veins—there is only a need for an individualized approach. If blood collection has been challenging in the past, it does not necessarily mean that it will be difficult the next time. Trust us.
It is also a misconception that bruising after a blood draw is caused solely by a punctured vein. In reality, if the puncture site is not compressed for 5–10 minutes after the procedure, bruising is much more likely to occur.
Another common misunderstanding is that obtaining a venous blood sample from a child is particularly difficult. At Nadezhda Hospital, we have extensive experience in this area, successfully perform pediatric blood collection every day, and handle this challenge with confidence.
11. What does working at Nadezhda mean to you emotionally?
Working here brings a wide range of emotions—joy, laughter, excitement, and sometimes sadness. The emotional palette is incredibly diverse. Let me give just one example: although we are only one part of the journey that many families take to fulfill their dream of having a child, we in the Clinical Laboratory share every step of that journey with them.
We celebrate positive pregnancy tests together with families, we feel their disappointment when treatment is unsuccessful, and we encourage and support them through every moment of this deeply personal and often difficult struggle.
For me, the most rewarding moments are meeting people who have finally fulfilled their long-held dream of becoming parents. It is truly moving. In those moments, I realize that it is impossible to separate work from emotion, because empathy and emotion are precisely what make us human.
