DHT Hb 523 Haemoglobinometer

Hemoglobinometer
DHT Hb523

Hospital report

Comparison of results of DHT Portable Hemoglobinometer estimations
with those using the Sysmex SE9000 Haematology Analyser.

The following trial was performed by Dr.T.Healy at Edinburgh Paediatric Hospital, UK in October 1997on behalf of Developing Health Technology, UK.
The DHT Hb-523 Portable Hemoglobinometer from Developing Health Technology was tested alongside the Sysmex SE9000 instrument used routinely in the hospital laboratory.
Report prepared by Developing Health Technology using data and comments provided by Tom Healy Temperature: 22° CReagents: 0.04% Ammonia solution.Whole Blood between 4 and 24 hours old, random selection, anticoagulated using EDTA and stored at room temperature before analysis. Analysed samples = 31

Sample	Sysmex	DHT Hb-523
1	2.6	2.3
2	3.4	3.2
3	5.5	5.6
4	6.9	7.1
5	4.4	6
6	6.6	7.3
7	8.8	9.6
8	11	12.1
9	13.4	15
10	15.4	17.3
11	18.3	20.3
12	20.4	22.2
13	22.5	24.8
14	16.3	15.8
15	9.8	11.2
16	8.6	9.3
17	10.7	11.4
18	12.5	12.5
19	11.9	12.9
20	10.6	12.2
21	13.8	14.8
22	9.2	10.5
23	12.6	12.8
24	9.4	10
25	11.7	12.5
26	13.4	13.9
27	12.3	12.8
28	10.4	11.8
29	12.6	14.1
30	12.1	13.4
31	12.4	12.5
Intercept	Slope	Correlation
0.20302	1.1	0.991713

"The instrument offers good reproducibility, was found to correlate exceptionally well at low levels @ 3-7 (Anaemia levels) and the variance at ‘normal’ levels is not clinically significant.
There appeared to be a larger variance in values from neonates due to transient HbF but this was not studied in depth, as the main use for Developing Health Technology would not be on neonates.
For the higher levels found in polycythaemia it may be that a double dilution of the sample may suffice to bring values into a level where the correlation is acceptable."

In comparing results, it should be borne in mind that the DHT Haemoglobinometer is specifically designed to detect various forms of Haemoglobin with equal sensitivity.
Forms other than Oxyhaemoglobin (HbO₂), though present in small amounts, thus contribute proportionally to the total Hb value. Conventional measurements at 540 nm with ammonia haemolysate will result in Methaemoglobin (Hi) and Sulphaemoglobin (SHb) being detected at about half the sensitivity of Oxyhaemoglobin (HbO₂) and thus contributing less than the proportion present! Using a conventional ferricyanide-cyanide reagent method, Sulphaemoglobin is not detected and erroneously low total Hb measurements will result if high levels of SHb are present.

conclusion

This was a simple comparison test between the two instruments; no suggestion that the Sysmex is more accurate is made. Ideally the two instruments would be compared against accurate standards or against results obtained using a spectrophotometer.
As our major interest is the requirements of developing countries, our conclusion is based on what is suitable for their needs. There has long been a need in developing countries for an accurate, simple to use device at a reasonable initial cost and zero or negligible ongoing consumable costs.
We are impressed with the ruggedness, accuracy and ease of use of this DHT Hb instrument. The lack of expensive or difficult to obtain consumables is a major benefit. The instrument is self-powered by supplied AA alkaline batteries, with an expected life of five years or about one million tests, although a mains adaptor is also available.

The DHT Hemoglobinometer offers vastly superior accuracy and reproducibility over visual comparison type instruments, yet it combines simplicity of use with low initial and ongoing cost.