Bernard J. Birkett
Senior Vice President & Chief Financial Officer at West Pharmaceutical Services
Thank you, Eric, and good morning. So let's review the numbers in more detail. We'll first look at Q4, 2021 revenues and profits, where we saw continued strong sales and EPS growth led by strong revenue performance in each of our proprietary market units. I will take you through the margin growth we saw on the quarter, as well as some balance sheet takeaways. And finally, we will review our 2022 guidance.
First up Q4, our financial results are summarized on Slide 10 and the reconciliation of non-US GAAP measures are described in Slides 19 to 22. We recorded net sales of $730.8 million in the quarter, representing organic sales growth of 28.3%. COVID related net revenues are estimated to have been approximately $124 million in the quarter. These net revenues include our assessment of components associated with vaccines, treatment and diagnosis of COVID-19 patients offset by lower sales to customers affected by lower volumes due to the pandemic.
Looking at Slide 11, proprietary product sales grew organically by 36.8% in the quarter. High value products, which made up approximately 74% of proprietary product sales in the quarter grew double digits and had solid momentum across all of our market units in Q4. Looking at the performance of the market units, the biologics market unit delivered strong double digit growth led by Novapure and Westar components. The generics and pharma market units also experienced double digit growth led by sales of FluroTec and Westar components.
And contract manufacturing organic net sales declined by 2.1% in the fourth quarter, primarily driven by lower sales of healthcare related medical devices. We continue to see improvement in gross profits. We recorded $300.6 million in gross profits, $89.5 million or 42.4% above Q4 of last year, and our gross profit margin of 41.1% with a 470 basis point expansion from the same period last year. We saw improvement in adjusted operating profit with $189.2 million recorded this quarter compared to $119.1 million in the same period last year for 58.9% increase. Our adjusted operating profit margin of 25.9% was a 540 basis point increase from the same period last year. Finally, adjusted diluted EPS grew 52% for Q4 excluding stock based compensation tax benefit of $0.06 in Q4. EPS grew by approximately 58%.
So let's review the growth drivers in both revenue and profits. On Slide 12, we show the contributions to sales growth in the quarter. Volume and mix contributed $153 million or 26.4 percentage points of growth, including approximately $78 million of incremental volume driven by COVID-19 related net demand. Sales price increases contributed $11.3 million or 1.9 percentage points of growth.
Looking at margin performance. Slide 13 shows our consolidated gross profit margin of 41.1% for Q4, 2021, up from 36.4% in Q4, 2020. Proprietary products fourth quarter gross profit margin 46.3% was 460 basis points above the margin achieved in the fourth quarter of 2020. The key drivers for the continued improvements in proprietary products gross profit margin were favorable mix of product sold driven by growth in high value products, production efficiencies, sales price increases, partially offset by increased overhead costs, inclusive of compensation. Contract manufacturing fourth quarter gross profit margin of 16.5% was 70 basis points below the margin achieved in the fourth quarter of 2020. The decrease in margin is largely attributed to increased raw material cost and a mix of product sold.
Now let's look at our balance sheet and review how we've done in terms of generating more cash. On Slide 14, we have listed some key cash flow metrics. Operating cash flow was $584 million for the year, an increase of $111.5 million compared to the same period last year, a 23.6% increase. Operating cash flow in the period was adversely impacted by a working capital increase as well as an increase in tax payments. In 2021, we spent over $253 million on capital expenditures, a 45% increase over 2020. The majority of the incremental capex has been leveraged to increase our high value product manufacturing capacity within our existing facilities. We expanded capacity at 13 existing sites, the 13 major facility modifications and over 400 pieces of equipment all while keeping pace with the growing demand.
We have continued to increase capacity at our HVP sites in the U.S., Germany, Ireland, and in Singapore and we have been able to leverage our existing asset base to support proprietary products manufacturing. For example, our Williamsport Pennsylvania site formally a contract manufacturing site will be transformed with over half its manufacturing capacity to support proprietary products with elastomer mixing and batch off line. And this leverage is a close proximity to our HVP site at Jersey Shore.
As we flex our global infrastructure with the phase capacity expansion, we are well-positioned for the continued growth in 2022. Working capital of approximately $1.1 billion increased by $277.6 million from 2020, primarily due to higher accounts receivable from our increased sales, higher inventory levels and an increase in our cash position. Our cash balance at December 31, was $762.6 million, was $147.1 million higher in our December 2020 balance. The increase in cash is primarily due to our strong operating results in the period offset by our share repurchase program and higher capex.
Turning to guidance. Slide 15 provides a high level summary. Full-year 2022 net sales guidance will be in a range of $3.05 billion to $3.075 billion. There is an estimated headwind of $70 million based on current foreign exchange rates. We expect organic sales growth to be approximately 10%. This comp -- comprises a mid-teen growth in our proprietary business. The forecast includes mid-teen growth in our base business and mid-teen growth in our net COVID related revenues.
For contract manufacturing, we are forecasting low-to-mid single digit negative growth in 2022. We do expect contract manufacturing to return to growth in 2023. We expect our full-year 2022 reports of diluted EPS guidance to be in a range of $9.20 to $9.35, also our capex guidance is $380 million for the year. There are some key elements I want to bring your attention to as you review our guidance. Estimated FX headwind on EPS had an impact of approximately $0.21 based on current foreign currency exchange rates and our guidance excludes future tax benefits from stock based compensation.
To summarize the key takeaways for the fourth quarter, strong topline growth in proprietary. Gross profit margin improvement, growth in operating profit margin, growth in adjusted diluted EPS and growth in operating cash flow delivering in line with our pillars of execute, innovate, and grow.
I'd now like to turn the call back over to Eric.
