Exclusion of Unsuitable Blood Sample for Quantitative of Carbon Monoxide Hemoglobin Analysis Using Different Calculation Method of Regression Analysis (DCR)

Abstract Point of care (POC) testing of International Normalized Ratio (INR) for monitoring warfarin therapy is rapidly becoming procedure of choice for patients requiring long term oral anticoagulation. This method allows for fingerstick blood sample to be used for INR testing at the point of service with immediate dose modification as needed. Most patients prefer a fingerstick method for blood draw to venipuncture. It is not known if venipuncture blood sample can be used for testing on POC machines. A significant number of patients in an oncology practice need additional laboratory testing on the same day as INR testing. These patients therefore get a fingerstick for POC INR testing and a venipuncture for other tests. We compared results of INR from venipuncture sample run on a POC machine (CoaguChek monitor) using CoaguChek test strips (ISI-2.0) with the INR performed on MDA analyzer (ISI-2.0). Blood samples from 24 patients on warfarin therapy were drawn from antecubital vein by a clean stick in a 10 cc plastic syringe. A drop of blood was immediately placed on the CoaguCheck test strip. Next the same blood sample was used to fill a 3.2% sodium citrate tube for testing on MDA analyzer. Results were analyzed using regression analysis; the correlation coefficient (r), slope and intercept were determined and following graph of the regression analysis was generated (see figure 1). Conclusions: These results show a good correlation (r-value> 0.9) between the results of INR obtained on CoaguChek POC machine and the MDA analyzer using venipuncture blood sample. The preferred method to obtain blood sample for POC INR monitoring must remain fingerstick sample as per manufacturer’s recommendations. However, for those patients who need more than one blood sample done on the same day, a venipuncture sample as described above gives acceptable results when tested on CoaguCheck machine. Figure Figure

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Carbon monoxide in blood: analytical method and sources of error

Journal of Applied Physiology ◽

10.1152/jappl.1964.19.3.510 ◽

1964 ◽

Vol 19 (3) ◽

pp. 510-515 ◽

Cited By ~ 41

Author(s):

R. F. Coburn ◽

G. K. Danielson ◽

W. S. Blakemore ◽

R. E. Forster

Keyword(s):

Carbon Monoxide ◽

Blood Sample ◽

Analytical Method ◽

Blood Gases ◽

Metallic Mercury ◽

Sources Of Error ◽

Hemoglobin Oxidation ◽

Infrared Analyzer

A method is described for the analysis of small concentrations of carboxyhemoglobin in blood in which the CO is dissociated from the hemoglobin by oxidizing the latter to methemoglobin with ferricyanide and measured as a gas in an infrared analyzer. The method has a sd of ±0.006 ml/100 ml in the range from 0.1 to 1.0 ml/100 ml. Data are presented which indicate that CO can be formed in a blood sample in vitro if the temperature during oxidation with ferricyanide is higher than about 60 C, if the pH of the reacting solution is 10 or higher, and if metallic mercury is not present during the reaction. It was demonstrated that additional CO is not formed during the analysis with the method described and that the method is highly specific for CO. blood carboxyhemoglobin; carbon monoxide; blood gases; carbon monoxide production; hemoglobin oxidation Submitted on July 19, 1963

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Carbon monoxide in blood: an improved microliter blood-sample collection system, with rapid analysis by gas chromatography.

Clinical Chemistry ◽

10.1093/clinchem/30.8.1382 ◽

1984 ◽

Vol 30 (8) ◽

pp. 1382-1386 ◽

Cited By ~ 81

Author(s):

H J Vreman ◽

L K Kwong ◽

D K Stevenson

Keyword(s):

Gas Chromatography ◽

Carbon Monoxide ◽

Blood Sample ◽

Premature Infants ◽

Rapid Analysis ◽

Analysis Time ◽

Sensitive Assay ◽

Sample Collection ◽

Collection System ◽

Significant Difference

Abstract We examined the sensitive assay for carboxyhemoglobin based on reaction with K3Fe(CN)6 and gas chromatography of the liberated CO. Our improvements included increased baseline stability, shorter analysis time, and simpler standardization. EDTA-containing Vacutainer Tubes (lavender-stoppered) increase the carboxyhemoglobin content of blood stored in them. The carboxyhemoglobin content of blood stored in capillary tubes containing solid heparin and saponin remained stable for two weeks. Using our improved procedures, we measured the carboxyhemoglobin content of blood from adults and neonates collected via venipuncture or heel or fingersticks. We observed no significant difference in carboxyhemoglobin content of blood obtained by venipuncture or heel stick for premature infants, 0.19 +/- 0.04 vs 0.18 +/- 0.03 mL of CO per 100 mL of blood, respectively (mean +/- SD). Nonsmoking adults (n = 19) had CO values (mean +/- SD) of 0.19 +/- 0.03 and 0.17 +/- 0.04 mL per 100 mL of blood, and smoking adults (n = 7) gave CO values of 0.96 +/- 0.49 and 0.91 +/- 0.49 mL/dL, for venipuncture and fingerstick, respectively.

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