Analytical Evaluation of Point-of-Care Finecare™ Procalcitonin Rapid Quantitative Test in Sepsis Population as Compared with Elecsys^® BRAHMS Procalcitonin Immunoassay

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

Please pay attention to the following comments and questions, pertaining to your manuscript:

1.      According to the Abstract, overall 40 plasma samples were analyzed. According to the Table 1, overall 42 samples were analyzed. Please make this point clear.

2.      Lines 89-90. The PCT levels obtained from plasma samples using the Finecare™ POC PCT were compared with the plasma Elecsys® BRAHMS PCT results obtained from the Cobas e411analyzer. Finecare™ POC test should actually function as a bedside test, which means using whole blood samples. Please explain why you didn’t compare the results of the whole blood samples analyzed by Finecare™ POC test and used instead the plasma results for your comparison.

3.      Study population. This is not clear if you worked exclusively with an ICU population and if sepsis was the admission diagnosis. Please add this information to your text.

4.      How many hours or days after the admission did you perform the tests?

5.      Did the study participants receive any antibiotic therapy during the tests?

6.      Line 236. You probably mean: In our institution mix ICU ward. Please correct.

Best Regards

Comments on the Quality of English Language

minor changes

Author Response

1. According to the Abstract, overall 40 plasma samples were analyzed. According to the Table 1, overall 42 samples were analyzed. Please make this point clear. Table 1 changed to 40
2. Lines 89-90. The PCT levels obtained from plasma samples using the Finecare™ POC PCT were compared with the plasma Elecsys® BRAHMS PCT results obtained from the Cobas e411analyzer. Finecare™ POC test should actually function as a bedside test, which means using whole blood samples. Please explain why you didn’t compare the results of the whole blood samples analyzed by Finecare™ POC test and used instead the plasma results for your comparison. We already compared and published in our previous study. We want to know the result of similar type of sample for better comparison. Nowadays there is bedside centrifuge machine in our ICU. Therefore, it can be performed within 10-15 minutes.  In manuscripts under section introduction second last paragraph :A prior study demonstrated that the type of sample used can affect the precision of procalcitonin (PCT) testing [6]. Specifically, it found that whole blood samples had higher coefficients of variation (CV), indicating lower precision. In contrast, the precision was better when using plasma samples for point-of-care PCT testing. 
3. Study population. This is not clear if you worked exclusively with an ICU population and if sepsis was the admission diagnosis. Please add this information to your text. Yes , ICU patient with a diagnosis of sepsis.   Full sentence in manuscripts added under methods : The study employed a random sampling strategy to identify participants. Eligible patients were those admitted to the intensive care unit within the previous 24 to 48 hours, carrying a diagnosis of sepsis, and receiving antibiotic treatment for sepsis management. 
4. How many hours or days after the admission did you perform the tests? within 24-48 hours
5. Did the study participants receive any antibiotic therapy during the tests? Yes
6. Line 236. You probably mean: In our institution mix ICU ward. Please correct. Yes

Reviewer 2 Report

Comments and Suggestions for Authors

How much does it cost to analyze one sample, that is, blood/serum from one patient at one research point? Is this or that system closed or open, that is, do the systems allow the use of reagents from other manufacturers? According to the authors, how many minimum patients per day are needed to justify the purchase of a particular system? The nosological characteristics of patients and the severity of sepsis in both groups should be given and their comparability should be shown.

Author Response

How much does it cost to analyze one sample, that is, blood/serum from one patient at one research point? The cost for point-of-care PCT testing is approximately $25 USD, while laboratory-based PCT testing costs around $60 USD. These figures represent only the prices of the PCT test kits or reagents themselves. Additional expenses, such as those for medical technologists, storage facilities, and equipment used to perform the tests, are not included in these amounts.

Is this or that system closed or open, that is, do the systems allow the use of reagents from other manufacturers? Closed.

According to the authors, how many minimum patients per day are needed to justify the purchase of a particular system?

One advantage of the point-of-care PCT testing used in our study is the longer expiration date of around 2 years, and since the kits come in boxes of 25, using some kits does not affect the remaining kits in the same box. The minimum purchase quantity is 25 test kits per box, which costs between $300-400 USD per box. In comparison, laboratory-based PCT testing is more expensive, with each box costing $1500-2000 USD but allowing for 100 tests to be performed. However, in practical usage, the number of tests that can be performed from a laboratory PCT kit depends on the daily testing volume and frequency. Each day, laboratory PCT testing requires calibration for every PCT test planned, so if a bulk order of 99 samples is received in one day, only one test is needed for calibration. But in the worst-case scenario of only one PCT test being sent to the lab per day for 50 days, only 50 tests can be performed because an additional test is used for daily calibration over those 50 days. Therefore, the minimum number of tests required is 25 tests within the 2-year expiration date for point-of-care, and 50 PCT tests within the expiration date per box of laboratory PCT reagent. 

The nosological characteristics of patients and the severity of sepsis in both groups should be given and their comparability should be shown. Characteristics added as suggested. Both groups have the similar characteristic in view of the same samples used for analysis of different methods (point of care in bedside icu vs laboratory automated pct)

The study population was predominantly male, with a majority age of 51 years. A significant proportion, 68%, had non-oliguric acute kidney injury, as evidenced by elevated creatinine levels but the presence of normal urine output. All patients included in the study exhibited elevated total white blood cell counts, confirming their sepsis diagnosis. Most of the study participants required mechanical ventilation, indicating the severity of their condition. Approximately 40% of the patients were in septic shock, as evidenced by the use of noradrenaline to maintain a mean arterial pressure above 65 mmHg despite adequate fluid resuscitation (Table 1).

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

thank you for providing comprehensive and convincing answers to the questions and queries expressed by me and the other Reviewers and revised your manuscript extensively. I have no further questions, pertaining to your manuscript.

Best Regards